Nyaaori/rockbox
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
rockbox/apps/plugins/jpeg.c

1971 lines
66 KiB
C
Raw Blame History

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* JPEG image viewer
* (This is a real mess if it has to be coded in one single C file)
*
* Copyright (C) 2004 Jörg Hohensohn aka [IDC]Dragon
* Grayscale framework (c) 2004 Jens Arnold
* Heavily borrowed from the IJG implementation (c) Thomas G. Lane
* Small & fast downscaling IDCT (c) 2002 by Guido Vollbeding JPEGclub.org
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef SIMULATOR /* not for simulator by now */
#include "plugin.h"
#if defined(HAVE_LCD_BITMAP) && (LCD_DEPTH < 4)
#include "gray.h"
PLUGIN_HEADER
/* variable button definitions */
#if CONFIG_KEYPAD == RECORDER_PAD
#define JPEG_ZOOM_IN BUTTON_PLAY
#define JPEG_ZOOM_OUT BUTTON_ON
#elif CONFIG_KEYPAD == ONDIO_PAD
#define JPEG_ZOOM_PRE BUTTON_MENU
#define JPEG_ZOOM_IN (BUTTON_MENU | BUTTON_REL)
#define JPEG_ZOOM_OUT (BUTTON_MENU | BUTTON_REPEAT)
#elif CONFIG_KEYPAD == IRIVER_H100_PAD
#define JPEG_ZOOM_IN BUTTON_SELECT
#define JPEG_ZOOM_OUT BUTTON_MODE
#endif
/******************************* Globals ***********************************/
static struct plugin_api* rb;
/* for portability of below JPEG code */
#define MEMSET(p,v,c) rb->memset(p,v,c)
#define MEMCPY(d,s,c) rb->memcpy(d,s,c)
#define INLINE static inline
#define ENDIAN_SWAP16(n) n /* only for poor little endian machines */
/**************** begin JPEG code ********************/
/* LUT for IDCT, this could also be used for gamma correction */
const unsigned char range_limit[1024] =
{
128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,
32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,
64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,
80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,
96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,
112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127
};
/* IDCT implementation */
#define CONST_BITS 13
#define PASS1_BITS 2
/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
* causing a lot of useless floating-point operations at run time.
* To get around this we use the following pre-calculated constants.
* If you change CONST_BITS you may want to add appropriate values.
* (With a reasonable C compiler, you can just rely on the FIX() macro...)
*/
#define FIX_0_298631336 2446 /* FIX(0.298631336) */
#define FIX_0_390180644 3196 /* FIX(0.390180644) */
#define FIX_0_541196100 4433 /* FIX(0.541196100) */
#define FIX_0_765366865 6270 /* FIX(0.765366865) */
#define FIX_0_899976223 7373 /* FIX(0.899976223) */
#define FIX_1_175875602 9633 /* FIX(1.175875602) */
#define FIX_1_501321110 12299 /* FIX(1.501321110) */
#define FIX_1_847759065 15137 /* FIX(1.847759065) */
#define FIX_1_961570560 16069 /* FIX(1.961570560) */
#define FIX_2_053119869 16819 /* FIX(2.053119869) */
#define FIX_2_562915447 20995 /* FIX(2.562915447) */
#define FIX_3_072711026 25172 /* FIX(3.072711026) */
/* Multiply an long variable by an long constant to yield an long result.
* For 8-bit samples with the recommended scaling, all the variable
* and constant values involved are no more than 16 bits wide, so a
* 16x16->32 bit multiply can be used instead of a full 32x32 multiply.
* For 12-bit samples, a full 32-bit multiplication will be needed.
*/
#define MULTIPLY16(var,const) (((short) (var)) * ((short) (const)))
/* Dequantize a coefficient by multiplying it by the multiplier-table
* entry; produce an int result. In this module, both inputs and result
* are 16 bits or less, so either int or short multiply will work.
*/
/* #define DEQUANTIZE(coef,quantval) (((int) (coef)) * (quantval)) */
#define DEQUANTIZE MULTIPLY16
/* Descale and correctly round an int value that's scaled by N bits.
* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
* the fudge factor is correct for either sign of X.
*/
#define DESCALE(x,n) (((x) + (1l << ((n)-1))) >> (n))
#define RANGE_MASK (255 * 4 + 3) /* 2 bits wider than legal samples */
/*
* Perform dequantization and inverse DCT on one block of coefficients,
* producing a reduced-size 1x1 output block.
*/
void idct1x1(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
{
(void)skip_line; /* unused */
*p_byte = range_limit[(inptr[0] * quantptr[0] >> 3) & RANGE_MASK];
}
/*
* Perform dequantization and inverse DCT on one block of coefficients,
* producing a reduced-size 2x2 output block.
*/
void idct2x2(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
{
int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5;
unsigned char* outptr;
/* Pass 1: process columns from input, store into work array. */
/* Column 0 */
tmp4 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
tmp5 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
tmp0 = tmp4 + tmp5;
tmp2 = tmp4 - tmp5;
/* Column 1 */
tmp4 = DEQUANTIZE(inptr[8*0+1], quantptr[8*0+1]);
tmp5 = DEQUANTIZE(inptr[8*1+1], quantptr[8*1+1]);
tmp1 = tmp4 + tmp5;
tmp3 = tmp4 - tmp5;
/* Pass 2: process 2 rows, store into output array. */
/* Row 0 */
outptr = p_byte;
outptr[0] = range_limit[(int) DESCALE(tmp0 + tmp1, 3)
& RANGE_MASK];
outptr[1] = range_limit[(int) DESCALE(tmp0 - tmp1, 3)
& RANGE_MASK];
/* Row 1 */
outptr = p_byte + skip_line;
outptr[0] = range_limit[(int) DESCALE(tmp2 + tmp3, 3)
& RANGE_MASK];
outptr[1] = range_limit[(int) DESCALE(tmp2 - tmp3, 3)
& RANGE_MASK];
}
/*
* Perform dequantization and inverse DCT on one block of coefficients,
* producing a reduced-size 4x4 output block.
*/
void idct4x4(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
{
int tmp0, tmp2, tmp10, tmp12;
int z1, z2, z3;
int * wsptr;
unsigned char* outptr;
int ctr;
int workspace[4*4]; /* buffers data between passes */
/* Pass 1: process columns from input, store into work array. */
wsptr = workspace;
for (ctr = 0; ctr < 4; ctr++, inptr++, quantptr++, wsptr++)
{
/* Even part */
tmp0 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
tmp2 = DEQUANTIZE(inptr[8*2], quantptr[8*2]);
tmp10 = (tmp0 + tmp2) << PASS1_BITS;
tmp12 = (tmp0 - tmp2) << PASS1_BITS;
/* Odd part */
/* Same rotation as in the even part of the 8x8 LL&M IDCT */
z2 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
z3 = DEQUANTIZE(inptr[8*3], quantptr[8*3]);
z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
tmp0 = DESCALE(z1 + MULTIPLY16(z3, - FIX_1_847759065), CONST_BITS-PASS1_BITS);
tmp2 = DESCALE(z1 + MULTIPLY16(z2, FIX_0_765366865), CONST_BITS-PASS1_BITS);
/* Final output stage */
wsptr[4*0] = (int) (tmp10 + tmp2);
wsptr[4*3] = (int) (tmp10 - tmp2);
wsptr[4*1] = (int) (tmp12 + tmp0);
wsptr[4*2] = (int) (tmp12 - tmp0);
}
/* Pass 2: process 4 rows from work array, store into output array. */
wsptr = workspace;
for (ctr = 0; ctr < 4; ctr++)
{
outptr = p_byte + (ctr*skip_line);
/* Even part */
tmp0 = (int) wsptr[0];
tmp2 = (int) wsptr[2];
tmp10 = (tmp0 + tmp2) << CONST_BITS;
tmp12 = (tmp0 - tmp2) << CONST_BITS;
/* Odd part */
/* Same rotation as in the even part of the 8x8 LL&M IDCT */
z2 = (int) wsptr[1];
z3 = (int) wsptr[3];
z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
tmp0 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
tmp2 = z1 + MULTIPLY16(z2, FIX_0_765366865);
/* Final output stage */
outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2,
CONST_BITS+PASS1_BITS+3)
& RANGE_MASK];
outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2,
CONST_BITS+PASS1_BITS+3)
& RANGE_MASK];
outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0,
CONST_BITS+PASS1_BITS+3)
& RANGE_MASK];
outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0,
CONST_BITS+PASS1_BITS+3)
& RANGE_MASK];
wsptr += 4; /* advance pointer to next row */
}
}
/*
* Perform dequantization and inverse DCT on one block of coefficients.
*/
void idct8x8(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
{
long tmp0, tmp1, tmp2, tmp3;
long tmp10, tmp11, tmp12, tmp13;
long z1, z2, z3, z4, z5;
int * wsptr;
unsigned char* outptr;
int ctr;
static int workspace[64]; /* buffers data between passes */
/* Pass 1: process columns from input, store into work array. */
/* Note results are scaled up by sqrt(8) compared to a true IDCT; */
/* furthermore, we scale the results by 2**PASS1_BITS. */
wsptr = workspace;
for (ctr = 8; ctr > 0; ctr--)
{
/* Due to quantization, we will usually find that many of the input
* coefficients are zero, especially the AC terms. We can exploit this
* by short-circuiting the IDCT calculation for any column in which all
* the AC terms are zero. In that case each output is equal to the
* DC coefficient (with scale factor as needed).
* With typical images and quantization tables, half or more of the
* column DCT calculations can be simplified this way.
*/
if ((inptr[8*1] | inptr[8*2] | inptr[8*3]
| inptr[8*4] | inptr[8*5] | inptr[8*6] | inptr[8*7]) == 0)
{
/* AC terms all zero */
int dcval = DEQUANTIZE(inptr[8*0], quantptr[8*0]) << PASS1_BITS;
wsptr[8*0] = wsptr[8*1] = wsptr[8*2] = wsptr[8*3] = wsptr[8*4]
= wsptr[8*5] = wsptr[8*6] = wsptr[8*7] = dcval;
inptr++; /* advance pointers to next column */
quantptr++;
wsptr++;
continue;
}
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
z2 = DEQUANTIZE(inptr[8*2], quantptr[8*2]);
z3 = DEQUANTIZE(inptr[8*6], quantptr[8*6]);
z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
tmp2 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
tmp3 = z1 + MULTIPLY16(z2, FIX_0_765366865);
z2 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
z3 = DEQUANTIZE(inptr[8*4], quantptr[8*4]);
tmp0 = (z2 + z3) << CONST_BITS;
tmp1 = (z2 - z3) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
/* Odd part per figure 8; the matrix is unitary and hence its
transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. */
tmp0 = DEQUANTIZE(inptr[8*7], quantptr[8*7]);
tmp1 = DEQUANTIZE(inptr[8*5], quantptr[8*5]);
tmp2 = DEQUANTIZE(inptr[8*3], quantptr[8*3]);
tmp3 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
z1 = tmp0 + tmp3;
z2 = tmp1 + tmp2;
z3 = tmp0 + tmp2;
z4 = tmp1 + tmp3;
z5 = MULTIPLY16(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
tmp0 = MULTIPLY16(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
tmp1 = MULTIPLY16(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
tmp2 = MULTIPLY16(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
tmp3 = MULTIPLY16(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
z1 = MULTIPLY16(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
z2 = MULTIPLY16(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
z3 = MULTIPLY16(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
z4 = MULTIPLY16(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
wsptr[8*0] = (int) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
wsptr[8*7] = (int) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
wsptr[8*1] = (int) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
wsptr[8*6] = (int) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
wsptr[8*2] = (int) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
wsptr[8*5] = (int) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
wsptr[8*3] = (int) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
wsptr[8*4] = (int) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
inptr++; /* advance pointers to next column */
quantptr++;
wsptr++;
}
/* Pass 2: process rows from work array, store into output array. */
/* Note that we must descale the results by a factor of 8 == 2**3, */
/* and also undo the PASS1_BITS scaling. */
wsptr = workspace;
for (ctr = 0; ctr < 8; ctr++)
{
outptr = p_byte + (ctr*skip_line);
/* Rows of zeroes can be exploited in the same way as we did with columns.
* However, the column calculation has created many nonzero AC terms, so
* the simplification applies less often (typically 5% to 10% of the time).
* On machines with very fast multiplication, it's possible that the
* test takes more time than it's worth. In that case this section
* may be commented out.
*/
#ifndef NO_ZERO_ROW_TEST
if ((wsptr[1] | wsptr[2] | wsptr[3]
| wsptr[4] | wsptr[5] | wsptr[6] | wsptr[7]) == 0)
{
/* AC terms all zero */
unsigned char dcval = range_limit[(int) DESCALE((long) wsptr[0],
PASS1_BITS+3) & RANGE_MASK];
outptr[0] = dcval;
outptr[1] = dcval;
outptr[2] = dcval;
outptr[3] = dcval;
outptr[4] = dcval;
outptr[5] = dcval;
outptr[6] = dcval;
outptr[7] = dcval;
wsptr += 8; /* advance pointer to next row */
continue;
}
#endif
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
z2 = (long) wsptr[2];
z3 = (long) wsptr[6];
z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
tmp2 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
tmp3 = z1 + MULTIPLY16(z2, FIX_0_765366865);
tmp0 = ((long) wsptr[0] + (long) wsptr[4]) << CONST_BITS;
tmp1 = ((long) wsptr[0] - (long) wsptr[4]) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
/* Odd part per figure 8; the matrix is unitary and hence its
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. */
tmp0 = (long) wsptr[7];
tmp1 = (long) wsptr[5];
tmp2 = (long) wsptr[3];
tmp3 = (long) wsptr[1];
z1 = tmp0 + tmp3;
z2 = tmp1 + tmp2;
z3 = tmp0 + tmp2;
z4 = tmp1 + tmp3;
z5 = MULTIPLY16(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
tmp0 = MULTIPLY16(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
tmp1 = MULTIPLY16(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
tmp2 = MULTIPLY16(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
tmp3 = MULTIPLY16(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
z1 = MULTIPLY16(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
z2 = MULTIPLY16(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
z3 = MULTIPLY16(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
z4 = MULTIPLY16(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp3,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[7] = range_limit[(int) DESCALE(tmp10 - tmp3,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[1] = range_limit[(int) DESCALE(tmp11 + tmp2,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[6] = range_limit[(int) DESCALE(tmp11 - tmp2,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[2] = range_limit[(int) DESCALE(tmp12 + tmp1,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[5] = range_limit[(int) DESCALE(tmp12 - tmp1,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[3] = range_limit[(int) DESCALE(tmp13 + tmp0,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
outptr[4] = range_limit[(int) DESCALE(tmp13 - tmp0,
CONST_BITS+PASS1_BITS+3) & RANGE_MASK];
wsptr += 8; /* advance pointer to next row */
}
}
/* JPEG decoder implementation */
#define HUFF_LOOKAHEAD 8 /* # of bits of lookahead */
struct derived_tbl
{
/* Basic tables: (element [0] of each array is unused) */
long mincode[17]; /* smallest code of length k */
long maxcode[18]; /* largest code of length k (-1 if none) */
/* (maxcode[17] is a sentinel to ensure huff_DECODE terminates) */
int valptr[17]; /* huffval[] index of 1st symbol of length k */
/* Back link to public Huffman table (needed only in slow_DECODE) */
int* pub;
/* Lookahead tables: indexed by the next HUFF_LOOKAHEAD bits of
the input data stream. If the next Huffman code is no more
than HUFF_LOOKAHEAD bits long, we can obtain its length and
the corresponding symbol directly from these tables. */
int look_nbits[1<<HUFF_LOOKAHEAD]; /* # bits, or 0 if too long */
unsigned char look_sym[1<<HUFF_LOOKAHEAD]; /* symbol, or unused */
};
#define QUANT_TABLE_LENGTH 64
/* for type of Huffman table */
#define DC_LEN 28
#define AC_LEN 178
struct huffman_table
{ /* length and code according to JFIF format */
int huffmancodes_dc[DC_LEN];
int huffmancodes_ac[AC_LEN];
};
struct frame_component
{
int ID;
int horizontal_sampling;
int vertical_sampling;
int quanttable_select;
};
struct scan_component
{
int ID;
int DC_select;
int AC_select;
};
struct bitstream
{
unsigned long get_buffer; /* current bit-extraction buffer */
int bits_left; /* # of unused bits in it */
unsigned char* next_input_byte;
unsigned char* input_end; /* upper limit +1 */
};
struct jpeg
{
int x_size, y_size; /* size of image (can be less than block boundary) */
int x_phys, y_phys; /* physical size, block aligned */
int x_mbl; /* x dimension of MBL */
int y_mbl; /* y dimension of MBL */
int blocks; /* blocks per MBL */
int restart_interval; /* number of MCUs between RSTm markers */
int store_pos[4]; /* for Y block ordering */
unsigned char* p_entropy_data;
unsigned char* p_entropy_end;
int quanttable[4][QUANT_TABLE_LENGTH]; /* raw quantization tables 0-3 */
int qt_idct[2][QUANT_TABLE_LENGTH]; /* quantization tables for IDCT */
struct huffman_table hufftable[2]; /* Huffman tables */
struct derived_tbl dc_derived_tbls[2]; /* Huffman-LUTs */
struct derived_tbl ac_derived_tbls[2];
struct frame_component frameheader[3]; /* Component descriptor */
struct scan_component scanheader[3]; /* currently not used */
int mcu_membership[6]; /* info per block */
int tab_membership[6];
};
/* possible return flags for process_markers() */
#define HUFFTAB 0x0001 /* with huffman table */
#define QUANTTAB 0x0002 /* with quantization table */
#define APP0_JFIF 0x0004 /* with APP0 segment following JFIF standard */
#define FILL_FF 0x0008 /* with 0xFF padding bytes at begin/end */
#define SOF0 0x0010 /* with SOF0-Segment */
#define DHT 0x0020 /* with Definition of huffman tables */
#define SOS 0x0040 /* with Start-of-Scan segment */
#define DQT 0x0080 /* with definition of quantization table */
/* Preprocess the JPEG JFIF file */
int process_markers(unsigned char* p_src, long size, struct jpeg* p_jpeg)
{
unsigned char* p_bytes = p_src;
int marker_size; /* variable length of marker segment */
int i, j, n;
int ret = 0; /* returned flags */
p_jpeg->p_entropy_end = p_src + size;
while (p_src < p_bytes + size)
{
if (*p_src++ != 0xFF) /* no marker? */
{
p_src--; /* it's image data, put it back */
p_jpeg->p_entropy_data = p_src;
break; /* exit marker processing */
}
switch (*p_src++)
{
case 0xFF: /* Fill byte */
ret |= FILL_FF;
case 0x00: /* Zero stuffed byte - entropy data */
p_src--; /* put it back */
continue;
case 0xC0: /* SOF Huff - Baseline DCT */
{
ret |= SOF0;
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
n = *p_src++; /* sample precision (= 8 or 12) */
if (n != 8)
{
return(-1); /* Unsupported sample precision */
}
p_jpeg->y_size = *p_src++ << 8; /* Highbyte */
p_jpeg->y_size |= *p_src++; /* Lowbyte */
p_jpeg->x_size = *p_src++ << 8; /* Highbyte */
p_jpeg->x_size |= *p_src++; /* Lowbyte */
n = (marker_size-2-6)/3;
if (*p_src++ != n || (n != 1 && n != 3))
{
return(-2); /* Unsupported SOF0 component specification */
}
for (i=0; i<n; i++)
{
p_jpeg->frameheader[i].ID = *p_src++; /* Component info */
p_jpeg->frameheader[i].horizontal_sampling = *p_src >> 4;
p_jpeg->frameheader[i].vertical_sampling = *p_src++ & 0x0F;
p_jpeg->frameheader[i].quanttable_select = *p_src++;
if (p_jpeg->frameheader[i].horizontal_sampling > 2
|| p_jpeg->frameheader[i].vertical_sampling > 2)
return -3; /* Unsupported SOF0 subsampling */
}
p_jpeg->blocks = n;
}
break;
case 0xC1: /* SOF Huff - Extended sequential DCT*/
case 0xC2: /* SOF Huff - Progressive DCT*/
case 0xC3: /* SOF Huff - Spatial (sequential) lossless*/
case 0xC5: /* SOF Huff - Differential sequential DCT*/
case 0xC6: /* SOF Huff - Differential progressive DCT*/
case 0xC7: /* SOF Huff - Differential spatial*/
case 0xC8: /* SOF Arith - Reserved for JPEG extensions*/
case 0xC9: /* SOF Arith - Extended sequential DCT*/
case 0xCA: /* SOF Arith - Progressive DCT*/
case 0xCB: /* SOF Arith - Spatial (sequential) lossless*/
case 0xCD: /* SOF Arith - Differential sequential DCT*/
case 0xCE: /* SOF Arith - Differential progressive DCT*/
case 0xCF: /* SOF Arith - Differential spatial*/
{
return (-4); /* other DCT model than baseline not implemented */
}
case 0xC4: /* Define Huffman Table(s) */
{
unsigned char* p_temp;
ret |= DHT;
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
p_temp = p_src;
while (p_src < p_temp+marker_size-2-17) /* another table */
{
int sum = 0;
i = *p_src & 0x0F; /* table index */
if (i > 1)
{
return (-5); /* Huffman table index out of range */
}
else if (*p_src++ & 0xF0) /* AC table */
{
for (j=0; j<16; j++)
{
sum += *p_src;
p_jpeg->hufftable[i].huffmancodes_ac[j] = *p_src++;
}
if(16 + sum > AC_LEN)
return -10; /* longer than allowed */
for (; j < 16 + sum; j++)
p_jpeg->hufftable[i].huffmancodes_ac[j] = *p_src++;
}
else /* DC table */
{
for (j=0; j<16; j++)
{
sum += *p_src;
p_jpeg->hufftable[i].huffmancodes_dc[j] = *p_src++;
}
if(16 + sum > DC_LEN)
return -11; /* longer than allowed */
for (; j < 16 + sum; j++)
p_jpeg->hufftable[i].huffmancodes_dc[j] = *p_src++;
}
} /* while */
p_src = p_temp+marker_size - 2; // skip possible residue
}
break;
case 0xCC: /* Define Arithmetic coding conditioning(s) */
return(-6); /* Arithmetic coding not supported */
case 0xD8: /* Start of Image */
case 0xD9: /* End of Image */
case 0x01: /* for temp private use arith code */
break; /* skip parameterless marker */
case 0xDA: /* Start of Scan */
{
ret |= SOS;
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
n = (marker_size-2-1-3)/2;
if (*p_src++ != n || (n != 1 && n != 3))
{
return (-7); /* Unsupported SOS component specification */
}
for (i=0; i<n; i++)
{
p_jpeg->scanheader[i].ID = *p_src++;
p_jpeg->scanheader[i].DC_select = *p_src >> 4;
p_jpeg->scanheader[i].AC_select = *p_src++ & 0x0F;
}
p_src += 3; /* skip spectral information */
}
break;
case 0xDB: /* Define quantization Table(s) */
{
ret |= DQT;
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
n = (marker_size-2)/(QUANT_TABLE_LENGTH+1); /* # of tables */
for (i=0; i<n; i++)
{
int id = *p_src++; /* ID */
if (id >= 4)
{
return (-8); /* Unsupported quantization table */
}
/* Read Quantisation table: */
for (j=0; j<QUANT_TABLE_LENGTH; j++)
p_jpeg->quanttable[id][j] = *p_src++;
}
}
break;
case 0xDD: /* Define Restart Interval */
{
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
p_jpeg->restart_interval = *p_src++ << 8; /* Highbyte */
p_jpeg->restart_interval |= *p_src++; /* Lowbyte */
p_src += marker_size-4; /* skip segment */
}
break;
case 0xDC: /* Define Number of Lines */
case 0xDE: /* Define Hierarchical progression */
case 0xDF: /* Expand Reference Component(s) */
case 0xE0: /* Application Field 0*/
case 0xE1: /* Application Field 1*/
case 0xE2: /* Application Field 2*/
case 0xE3: /* Application Field 3*/
case 0xE4: /* Application Field 4*/
case 0xE5: /* Application Field 5*/
case 0xE6: /* Application Field 6*/
case 0xE7: /* Application Field 7*/
case 0xE8: /* Application Field 8*/
case 0xE9: /* Application Field 9*/
case 0xEA: /* Application Field 10*/
case 0xEB: /* Application Field 11*/
case 0xEC: /* Application Field 12*/
case 0xED: /* Application Field 13*/
case 0xEE: /* Application Field 14*/
case 0xEF: /* Application Field 15*/
case 0xFE: /* Comment */
{
marker_size = *p_src++ << 8; /* Highbyte */
marker_size |= *p_src++; /* Lowbyte */
p_src += marker_size-2; /* skip segment */
}
break;
case 0xF0: /* Reserved for JPEG extensions */
case 0xF1: /* Reserved for JPEG extensions */
case 0xF2: /* Reserved for JPEG extensions */
case 0xF3: /* Reserved for JPEG extensions */
case 0xF4: /* Reserved for JPEG extensions */
case 0xF5: /* Reserved for JPEG extensions */
case 0xF6: /* Reserved for JPEG extensions */
case 0xF7: /* Reserved for JPEG extensions */
case 0xF8: /* Reserved for JPEG extensions */
case 0xF9: /* Reserved for JPEG extensions */
case 0xFA: /* Reserved for JPEG extensions */
case 0xFB: /* Reserved for JPEG extensions */
case 0xFC: /* Reserved for JPEG extensions */
case 0xFD: /* Reserved for JPEG extensions */
case 0x02: /* Reserved */
default:
return (-9); /* Unknown marker */
} /* switch */
} /* while */
return (ret); /* return flags with seen markers */
}
void default_huff_tbl(struct jpeg* p_jpeg)
{
static const struct huffman_table luma_table =
{
{
0x00,0x01,0x05,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B
},
{
0x00,0x02,0x01,0x03,0x03,0x02,0x04,0x03,0x05,0x05,0x04,0x04,0x00,0x00,0x01,0x7D,
0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
0x22,0x71,0x14,0x32,0x81,0x91,0xA1,0x08,0x23,0x42,0xB1,0xC1,0x15,0x52,0xD1,0xF0,
0x24,0x33,0x62,0x72,0x82,0x09,0x0A,0x16,0x17,0x18,0x19,0x1A,0x25,0x26,0x27,0x28,
0x29,0x2A,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,
0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,0xC3,0xC4,0xC5,
0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xE1,0xE2,
0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,
0xF9,0xFA
}
};
static const struct huffman_table chroma_table =
{
{
0x00,0x03,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,
0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B
},
{
0x00,0x02,0x01,0x02,0x04,0x04,0x03,0x04,0x07,0x05,0x04,0x04,0x00,0x01,0x02,0x77,
0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,0xA1,0xB1,0xC1,0x09,0x23,0x33,0x52,0xF0,
0x15,0x62,0x72,0xD1,0x0A,0x16,0x24,0x34,0xE1,0x25,0xF1,0x17,0x18,0x19,0x1A,0x26,
0x27,0x28,0x29,0x2A,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,0x48,
0x49,0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,0x68,
0x69,0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x82,0x83,0x84,0x85,0x86,0x87,
0x88,0x89,0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,0xA5,
0xA6,0xA7,0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,0xC3,
0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,
0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,
0xF9,0xFA
}
};
MEMCPY(&p_jpeg->hufftable[0], &luma_table, sizeof(luma_table));
MEMCPY(&p_jpeg->hufftable[1], &chroma_table, sizeof(chroma_table));
return;
}
/* Compute the derived values for a Huffman table */
void fix_huff_tbl(int* htbl, struct derived_tbl* dtbl)
{
int p, i, l, si;
int lookbits, ctr;
char huffsize[257];
unsigned int huffcode[257];
unsigned int code;
dtbl->pub = htbl; /* fill in back link */
/* Figure C.1: make table of Huffman code length for each symbol */
/* Note that this is in code-length order. */
p = 0;
for (l = 1; l <= 16; l++)
{ /* all possible code length */
for (i = 1; i <= (int) htbl[l-1]; i++) /* all codes per length */
huffsize[p++] = (char) l;
}
huffsize[p] = 0;
/* Figure C.2: generate the codes themselves */
/* Note that this is in code-length order. */
code = 0;
si = huffsize[0];
p = 0;
while (huffsize[p])
{
while (((int) huffsize[p]) == si)
{
huffcode[p++] = code;
code++;
}
code <<= 1;
si++;
}
/* Figure F.15: generate decoding tables for bit-sequential decoding */
p = 0;
for (l = 1; l <= 16; l++)
{
if (htbl[l-1])
{
dtbl->valptr[l] = p; /* huffval[] index of 1st symbol of code length l */
dtbl->mincode[l] = huffcode[p]; /* minimum code of length l */
p += htbl[l-1];
dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */
}
else
{
dtbl->maxcode[l] = -1; /* -1 if no codes of this length */
}
}
dtbl->maxcode[17] = 0xFFFFFL; /* ensures huff_DECODE terminates */
/* Compute lookahead tables to speed up decoding.
* First we set all the table entries to 0, indicating "too long";
* then we iterate through the Huffman codes that are short enough and
* fill in all the entries that correspond to bit sequences starting
* with that code.
*/
MEMSET(dtbl->look_nbits, 0, sizeof(dtbl->look_nbits));
p = 0;
for (l = 1; l <= HUFF_LOOKAHEAD; l++)
{
for (i = 1; i <= (int) htbl[l-1]; i++, p++)
{
/* l = current code's length, p = its index in huffcode[] & huffval[]. */
/* Generate left-justified code followed by all possible bit sequences */
lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l);
for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--)
{
dtbl->look_nbits[lookbits] = l;
dtbl->look_sym[lookbits] = htbl[16+p];
lookbits++;
}
}
}
}
/* zag[i] is the natural-order position of the i'th element of zigzag order.
* If the incoming data is corrupted, decode_mcu could attempt to
* reference values beyond the end of the array. To avoid a wild store,
* we put some extra zeroes after the real entries.
*/
static const int zag[] =
{
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63,
0, 0, 0, 0, 0, 0, 0, 0, /* extra entries in case k>63 below */
0, 0, 0, 0, 0, 0, 0, 0
};
void build_lut(struct jpeg* p_jpeg)
{
int i;
fix_huff_tbl(p_jpeg->hufftable[0].huffmancodes_dc,
&p_jpeg->dc_derived_tbls[0]);
fix_huff_tbl(p_jpeg->hufftable[0].huffmancodes_ac,
&p_jpeg->ac_derived_tbls[0]);
fix_huff_tbl(p_jpeg->hufftable[1].huffmancodes_dc,
&p_jpeg->dc_derived_tbls[1]);
fix_huff_tbl(p_jpeg->hufftable[1].huffmancodes_ac,
&p_jpeg->ac_derived_tbls[1]);
/* build the dequantization tables for the IDCT (De-ZiZagged) */
for (i=0; i<64; i++)
{
p_jpeg->qt_idct[0][zag[i]] = p_jpeg->quanttable[0][i];
p_jpeg->qt_idct[1][zag[i]] = p_jpeg->quanttable[1][i];
}
for (i=0; i<4; i++)
p_jpeg->store_pos[i] = i; /* default ordering */
/* assignments for the decoding of blocks */
if (p_jpeg->frameheader[0].horizontal_sampling == 2
&& p_jpeg->frameheader[0].vertical_sampling == 1)
{ /* 4:2:2 */
p_jpeg->blocks = 4;
p_jpeg->x_mbl = (p_jpeg->x_size+15) / 16;
p_jpeg->x_phys = p_jpeg->x_mbl * 16;
p_jpeg->y_mbl = (p_jpeg->y_size+7) / 8;
p_jpeg->y_phys = p_jpeg->y_mbl * 8;
p_jpeg->mcu_membership[0] = 0; /* Y1=Y2=0, U=2, V=3 */
p_jpeg->mcu_membership[1] = 0;
p_jpeg->mcu_membership[2] = 2;
p_jpeg->mcu_membership[3] = 3;
p_jpeg->tab_membership[0] = 0; /* DC, DC, AC, AC */
p_jpeg->tab_membership[1] = 0;
p_jpeg->tab_membership[2] = 1;
p_jpeg->tab_membership[3] = 1;
}
if (p_jpeg->frameheader[0].horizontal_sampling == 1
&& p_jpeg->frameheader[0].vertical_sampling == 2)
{ /* 4:2:2 vertically subsampled */
p_jpeg->store_pos[1] = 2; /* block positions are mirrored */
p_jpeg->store_pos[2] = 1;
p_jpeg->blocks = 4;
p_jpeg->x_mbl = (p_jpeg->x_size+7) / 8;
p_jpeg->x_phys = p_jpeg->x_mbl * 8;
p_jpeg->y_mbl = (p_jpeg->y_size+15) / 16;
p_jpeg->y_phys = p_jpeg->y_mbl * 16;
p_jpeg->mcu_membership[0] = 0; /* Y1=Y2=0, U=2, V=3 */
p_jpeg->mcu_membership[1] = 0;
p_jpeg->mcu_membership[2] = 2;
p_jpeg->mcu_membership[3] = 3;
p_jpeg->tab_membership[0] = 0; /* DC, DC, AC, AC */
p_jpeg->tab_membership[1] = 0;
p_jpeg->tab_membership[2] = 1;
p_jpeg->tab_membership[3] = 1;
}
else if (p_jpeg->frameheader[0].horizontal_sampling == 2
&& p_jpeg->frameheader[0].vertical_sampling == 2)
{ /* 4:2:0 */
p_jpeg->blocks = 6;
p_jpeg->x_mbl = (p_jpeg->x_size+15) / 16;
p_jpeg->x_phys = p_jpeg->x_mbl * 16;
p_jpeg->y_mbl = (p_jpeg->y_size+15) / 16;
p_jpeg->y_phys = p_jpeg->y_mbl * 16;
p_jpeg->mcu_membership[0] = 0;
p_jpeg->mcu_membership[1] = 0;
p_jpeg->mcu_membership[2] = 0;
p_jpeg->mcu_membership[3] = 0;
p_jpeg->mcu_membership[4] = 2;
p_jpeg->mcu_membership[5] = 3;
p_jpeg->tab_membership[0] = 0;
p_jpeg->tab_membership[1] = 0;
p_jpeg->tab_membership[2] = 0;
p_jpeg->tab_membership[3] = 0;
p_jpeg->tab_membership[4] = 1;
p_jpeg->tab_membership[5] = 1;
}
else if (p_jpeg->frameheader[0].horizontal_sampling == 1
&& p_jpeg->frameheader[0].vertical_sampling == 1)
{ /* 4:4:4 */
/* don't overwrite p_jpeg->blocks */
p_jpeg->x_mbl = (p_jpeg->x_size+7) / 8;
p_jpeg->x_phys = p_jpeg->x_mbl * 8;
p_jpeg->y_mbl = (p_jpeg->y_size+7) / 8;
p_jpeg->y_phys = p_jpeg->y_mbl * 8;
p_jpeg->mcu_membership[0] = 0;
p_jpeg->mcu_membership[1] = 2;
p_jpeg->mcu_membership[2] = 3;
p_jpeg->tab_membership[0] = 0;
p_jpeg->tab_membership[1] = 1;
p_jpeg->tab_membership[2] = 1;
}
}
/*
* These functions/macros provide the in-line portion of bit fetching.
* Use check_bit_buffer to ensure there are N bits in get_buffer
* before using get_bits, peek_bits, or drop_bits.
* check_bit_buffer(state,n,action);
* Ensure there are N bits in get_buffer; if suspend, take action.
* val = get_bits(n);
* Fetch next N bits.
* val = peek_bits(n);
* Fetch next N bits without removing them from the buffer.
* drop_bits(n);
* Discard next N bits.
* The value N should be a simple variable, not an expression, because it
* is evaluated multiple times.
*/
INLINE void check_bit_buffer(struct bitstream* pb, int nbits)
{
if (pb->bits_left < nbits)
{ /* nbits is <= 16, so I can always refill 2 bytes in this case */
unsigned char byte;
byte = *pb->next_input_byte++;
if (byte == 0xFF) /* legal marker can be byte stuffing or RSTm */
{ /* simplification: just skip the (one-byte) marker code */
pb->next_input_byte++;
}
pb->get_buffer = (pb->get_buffer << 8) | byte;
byte = *pb->next_input_byte++;
if (byte == 0xFF) /* legal marker can be byte stuffing or RSTm */
{ /* simplification: just skip the (one-byte) marker code */
pb->next_input_byte++;
}
pb->get_buffer = (pb->get_buffer << 8) | byte;
pb->bits_left += 16;
}
}
INLINE int get_bits(struct bitstream* pb, int nbits)
{
return ((int) (pb->get_buffer >> (pb->bits_left -= nbits))) & ((1<<nbits)-1);
}
INLINE int peek_bits(struct bitstream* pb, int nbits)
{
return ((int) (pb->get_buffer >> (pb->bits_left - nbits))) & ((1<<nbits)-1);
}
INLINE void drop_bits(struct bitstream* pb, int nbits)
{
pb->bits_left -= nbits;
}
/* re-synchronize to entropy data (skip restart marker) */
void search_restart(struct bitstream* pb)
{
pb->next_input_byte--; /* we may have overread it, taking 2 bytes */
/* search for a non-byte-padding marker, has to be RSTm or EOS */
while (pb->next_input_byte < pb->input_end &&
(pb->next_input_byte[-2] != 0xFF || pb->next_input_byte[-1] == 0x00))
{
pb->next_input_byte++;
}
pb->bits_left = 0;
}
/* Figure F.12: extend sign bit. */
#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
static const int extend_test[16] = /* entry n is 2**(n-1) */
{
0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000
};
static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
{
0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1
};
/* Decode a single value */
INLINE int huff_decode_dc(struct bitstream* bs, struct derived_tbl* tbl)
{
int nb, look, s, r;
check_bit_buffer(bs, HUFF_LOOKAHEAD);
look = peek_bits(bs, HUFF_LOOKAHEAD);
if ((nb = tbl->look_nbits[look]) != 0)
{
drop_bits(bs, nb);
s = tbl->look_sym[look];
check_bit_buffer(bs, s);
r = get_bits(bs, s);
s = HUFF_EXTEND(r, s);
}
else
{ /* slow_DECODE(s, HUFF_LOOKAHEAD+1)) < 0); */
long code;
nb=HUFF_LOOKAHEAD+1;
check_bit_buffer(bs, nb);
code = get_bits(bs, nb);
while (code > tbl->maxcode[nb])
{
code <<= 1;
check_bit_buffer(bs, 1);
code |= get_bits(bs, 1);
nb++;
}
if (nb > 16) /* error in Huffman */
{
s=0; /* fake a zero, this is most safe */
}
else
{
s = tbl->pub[16 + tbl->valptr[nb] + ((int) (code - tbl->mincode[nb])) ];
check_bit_buffer(bs, s);
r = get_bits(bs, s);
s = HUFF_EXTEND(r, s);
}
} /* end slow decode */
return s;
}
INLINE int huff_decode_ac(struct bitstream* bs, struct derived_tbl* tbl)
{
int nb, look, s;
check_bit_buffer(bs, HUFF_LOOKAHEAD);
look = peek_bits(bs, HUFF_LOOKAHEAD);
if ((nb = tbl->look_nbits[look]) != 0)
{
drop_bits(bs, nb);
s = tbl->look_sym[look];
}
else
{ /* slow_DECODE(s, HUFF_LOOKAHEAD+1)) < 0); */
long code;
nb=HUFF_LOOKAHEAD+1;
check_bit_buffer(bs, nb);
code = get_bits(bs, nb);
while (code > tbl->maxcode[nb])
{
code <<= 1;
check_bit_buffer(bs, 1);
code |= get_bits(bs, 1);
nb++;
}
if (nb > 16) /* error in Huffman */
{
s=0; /* fake a zero, this is most safe */
}
else
{
s = tbl->pub[16 + tbl->valptr[nb] + ((int) (code - tbl->mincode[nb])) ];
}
} /* end slow decode */
return s;
}
/* a JPEG decoder specialized in decoding only the luminance (b&w) */
int jpeg_decode(struct jpeg* p_jpeg, unsigned char* p_pixel, int downscale,
void (*pf_progress)(int current, int total))
{
struct bitstream bs; /* bitstream "object" */
static int block[64]; /* decoded DCT coefficients */
int width, height;
int skip_line; /* bytes from one line to the next (skip_line) */
int skip_strip, skip_mcu; /* bytes to next DCT row / column */
int x, y; /* loop counter */
unsigned char* p_byte; /* bitmap pointer */
void (*pf_idct)(unsigned char*, int*, int*, int); /* selected IDCT */
int k_need; /* AC coefficients needed up to here */
int zero_need; /* init the block with this many zeros */
int last_dc_val = 0;
int store_offs[4]; /* memory offsets: order of Y11 Y12 Y21 Y22 U V */
int restart = p_jpeg->restart_interval; /* MCUs until restart marker */
/* pick the IDCT we want, determine how to work with coefs */
if (downscale == 1)
{
pf_idct = idct8x8;
k_need = 64; /* all */
zero_need = 63; /* all */
}
else if (downscale == 2)
{
pf_idct = idct4x4;
k_need = 25; /* this far in zig-zag to cover 4*4 */
zero_need = 27; /* clear this far in linear order */
}
else if (downscale == 4)
{
pf_idct = idct2x2;
k_need = 5; /* this far in zig-zag to cover 2*2 */
zero_need = 9; /* clear this far in linear order */
}
else if (downscale == 8)
{
pf_idct = idct1x1;
k_need = 0; /* no AC, not needed */
zero_need = 0; /* no AC, not needed */
}
else return -1; /* not supported */
/* init bitstream, fake a restart to make it start */
bs.next_input_byte = p_jpeg->p_entropy_data;
bs.bits_left = 0;
bs.input_end = p_jpeg->p_entropy_end;
width = p_jpeg->x_phys / downscale;
height = p_jpeg->y_phys / downscale;
skip_line = width;
skip_strip = skip_line * (height / p_jpeg->y_mbl);
skip_mcu = (width/p_jpeg->x_mbl);
/* prepare offsets about where to store the different blocks */
store_offs[p_jpeg->store_pos[0]] = 0;
store_offs[p_jpeg->store_pos[1]] = 8 / downscale; /* to the right */
store_offs[p_jpeg->store_pos[2]] = width * 8 / downscale; /* below */
store_offs[p_jpeg->store_pos[3]] = store_offs[1] + store_offs[2]; /* r+b */
for(y=0; y<p_jpeg->y_mbl && bs.next_input_byte <= bs.input_end; y++)
{
p_byte = p_pixel;
p_pixel += skip_strip;
for (x=0; x<p_jpeg->x_mbl; x++)
{
int blkn;
/* Outer loop handles each block in the MCU */
for (blkn = 0; blkn < p_jpeg->blocks; blkn++)
{ /* Decode a single block's worth of coefficients */
int k = 1; /* coefficient index */
int s, r; /* huffman values */
int ci = p_jpeg->mcu_membership[blkn]; /* component index */
int ti = p_jpeg->tab_membership[blkn]; /* table index */
struct derived_tbl* dctbl = &p_jpeg->dc_derived_tbls[ti];
struct derived_tbl* actbl = &p_jpeg->ac_derived_tbls[ti];
/* Section F.2.2.1: decode the DC coefficient difference */
s = huff_decode_dc(&bs, dctbl);
if (ci == 0) /* only for Y component */
{
last_dc_val += s;
block[0] = last_dc_val; /* output it (assumes zag[0] = 0) */
/* coefficient buffer must be cleared */
MEMSET(block+1, 0, zero_need*sizeof(block[0]));
/* Section F.2.2.2: decode the AC coefficients */
for (; k < k_need; k++)
{
s = huff_decode_ac(&bs, actbl);
r = s >> 4;
s &= 15;
if (s)
{
k += r;
check_bit_buffer(&bs, s);
r = get_bits(&bs, s);
block[zag[k]] = HUFF_EXTEND(r, s);
}
else
{
if (r != 15)
{
k = 64;
break;
}
k += r;
}
} /* for k */
}
/* In this path we just discard the values */
for (; k < 64; k++)
{
s = huff_decode_ac(&bs, actbl);
r = s >> 4;
s &= 15;
if (s)
{
k += r;
check_bit_buffer(&bs, s);
drop_bits(&bs, s);
}
else
{
if (r != 15)
break;
k += r;
}
} /* for k */
if (ci == 0)
{ /* only for Y component */
pf_idct(p_byte+store_offs[blkn], block, p_jpeg->qt_idct[ti],
skip_line);
}
} /* for blkn */
p_byte += skip_mcu;
if (p_jpeg->restart_interval && --restart == 0)
{ /* if a restart marker is due: */
restart = p_jpeg->restart_interval; /* count again */
search_restart(&bs); /* align the bitstream */
last_dc_val = 0; /* reset decoder */
}
} /* for x */
if (pf_progress != NULL)
pf_progress(y, p_jpeg->y_mbl-1); /* notify about decoding progress */
} /* for y */
return 0; /* success */
}
/**************** end JPEG code ********************/
/**************** begin Application ********************/
/************************* Types ***************************/
struct t_disp
{
unsigned char* bitmap;
int width;
int height;
int stride;
int x, y;
};
/************************* Globals ***************************/
/* decompressed image in the possible sizes (1,2,4,8), wasting the other */
struct t_disp disp[9];
/* my memory pool (from the mp3 buffer) */
char print[32]; /* use a common snprintf() buffer */
unsigned char* buf; /* up to here currently used by image(s) */
int buf_size;
unsigned char* buf_root; /* the root of the images */
int root_size;
/************************* Implementation ***************************/
/* switch off overlay, for handling SYS_ events */
void cleanup(void *parameter)
{
(void)parameter;
gray_show(false);
}
#define VSCROLL (LCD_HEIGHT/8)
#define HSCROLL (LCD_WIDTH/10)
#define ZOOM_IN 100 // return codes for below function
#define ZOOM_OUT 101
/* interactively scroll around the image */
int scroll_bmp(struct t_disp* pdisp)
{
int lastbutton = 0;
/*empty the button queue first, to avoid unwanted scrolling */
rb->button_clear_queue();
while (true)
{
int button;
int move;
button = rb->button_get(true);
switch(button)
{
case BUTTON_LEFT:
case BUTTON_LEFT | BUTTON_REPEAT:
move = MIN(HSCROLL, pdisp->x);
if (move > 0)
{
gray_ub_scroll_right(move); /* scroll right */
pdisp->x -= move;
gray_ub_gray_bitmap_part(
pdisp->bitmap, pdisp->x, pdisp->y, pdisp->stride,
0, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
move, MIN(LCD_HEIGHT, pdisp->height)); /* w, h */
}
break;
case BUTTON_RIGHT:
case BUTTON_RIGHT | BUTTON_REPEAT:
move = MIN(HSCROLL, pdisp->width - pdisp->x - LCD_WIDTH);
if (move > 0)
{
gray_ub_scroll_left(move); /* scroll left */
pdisp->x += move;
gray_ub_gray_bitmap_part(
pdisp->bitmap, pdisp->x + LCD_WIDTH - move,
pdisp->y, pdisp->stride,
LCD_WIDTH - move, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
move, MIN(LCD_HEIGHT, pdisp->height)); /* w, h */
}
break;
case BUTTON_UP:
case BUTTON_UP | BUTTON_REPEAT:
move = MIN(VSCROLL, pdisp->y);
if (move > 0)
{
gray_ub_scroll_down(move); /* scroll down */
pdisp->y -= move;
gray_ub_gray_bitmap_part(
pdisp->bitmap, pdisp->x, pdisp->y, pdisp->stride,
MAX(0, (LCD_WIDTH-pdisp->width)/2), 0, /* x, y */
MIN(LCD_WIDTH, pdisp->width), move); /* w, h */
}
break;
case BUTTON_DOWN:
case BUTTON_DOWN | BUTTON_REPEAT:
move = MIN(VSCROLL, pdisp->height - pdisp->y - LCD_HEIGHT);
if (move > 0)
{
gray_ub_scroll_up(move); /* scroll up */
pdisp->y += move;
gray_ub_gray_bitmap_part(
pdisp->bitmap, pdisp->x,
pdisp->y + LCD_HEIGHT - move, pdisp->stride,
MAX(0, (LCD_WIDTH-pdisp->width)/2), LCD_HEIGHT - move, /* x, y */
MIN(LCD_WIDTH, pdisp->width), move); /* w, h */
}
break;
case JPEG_ZOOM_IN:
#ifdef JPEG_ZOOM_PRE
if (lastbutton != JPEG_ZOOM_PRE)
break;
#endif
return ZOOM_IN;
break;
case JPEG_ZOOM_OUT:
#ifdef JPEG_ZOOM_PRE
if (lastbutton != JPEG_ZOOM_PRE)
break;
#endif
return ZOOM_OUT;
break;
case BUTTON_OFF:
return PLUGIN_OK;
default:
if (rb->default_event_handler_ex(button, cleanup, NULL)
== SYS_USB_CONNECTED)
return PLUGIN_USB_CONNECTED;
break;
} /* switch */
if (button != BUTTON_NONE)
lastbutton = button;
} /* while (true) */
}
/********************* main function *************************/
/* debug function */
int wait_for_button(void)
{
int button;
do
{
button = rb->button_get(true);
} while ((button & BUTTON_REL) && button != SYS_USB_CONNECTED);
return button;
}
/* callback updating a progress meter while JPEG decoding */
void cb_progess(int current, int total)
{
rb->yield(); /* be nice to the other threads */
rb->scrollbar(0, LCD_HEIGHT-8, LCD_WIDTH, 8, total, 0,
current, HORIZONTAL);
rb->lcd_update_rect(0, LCD_HEIGHT-8, LCD_WIDTH, 8);
}
/* helper to align a buffer to a given power of two */
void align(unsigned char** ppbuf, int* plen, int align)
{
unsigned int orig = (unsigned int)*ppbuf;
unsigned int aligned = (orig + (align-1)) & ~(align-1);
*plen -= aligned - orig;
*ppbuf = (unsigned char*)aligned;
}
/* how far can we zoom in without running out of memory */
int min_downscale(int x, int y, int bufsize)
{
int downscale = 8;
if ((x/8) * (y/8) > bufsize)
return 0; /* error, too large, even 1:8 doesn't fit */
while ((x*2/downscale) * (y*2/downscale) < bufsize
&& downscale > 1)
{
downscale /= 2;
}
return downscale;
}
/* how far can we zoom out, to fit image into the LCD */
int max_downscale(int x, int y)
{
int downscale = 1;
while ((x/downscale > LCD_WIDTH || y/downscale > LCD_HEIGHT)
&& downscale < 8)
{
downscale *= 2;
}
return downscale;
}
/* return decoded or cached image */
struct t_disp* get_image(struct jpeg* p_jpg, int ds)
{
int w, h; /* used to center output */
int size; /* decompressed image size */
long time; /* measured ticks */
int status;
struct t_disp* p_disp = &disp[ds]; /* short cut */
if (p_disp->bitmap != NULL)
{
return p_disp; /* we still have it */
}
/* assign image buffer */
/* physical size needed for decoding */
size = (p_jpg->x_phys/ds) * (p_jpg->y_phys / ds);
if (buf_size <= size)
{ /* have to discard the current */
int i;
for (i=1; i<=8; i++)
disp[i].bitmap = NULL; /* invalidate all bitmaps */
buf = buf_root; /* start again from the beginning of the buffer */
buf_size = root_size;
}
/* size may be less when decoded (if height is not block aligned) */
size = (p_jpg->x_phys/ds) * (p_jpg->y_size / ds);
p_disp->bitmap = buf;
buf += size;
buf_size -= size;
rb->snprintf(print, sizeof(print), "decoding %d*%d",
p_jpg->x_size/ds, p_jpg->y_size/ds);
rb->lcd_puts(0, 3, print);
rb->lcd_update();
/* update image properties */
p_disp->width = p_jpg->x_size/ds;
p_disp->stride = p_jpg->x_phys / ds; /* use physical size for stride */
p_disp->height = p_jpg->y_size/ds;
/* the actual decoding */
time = *rb->current_tick;
#if !defined(SIMULATOR) && defined(HAVE_ADJUSTABLE_CPU_FREQ)
rb->cpu_boost(true);
status = jpeg_decode(p_jpg, p_disp->bitmap, ds, cb_progess);
rb->cpu_boost(false);
#else
status = jpeg_decode(p_jpg, p_disp->bitmap, ds, cb_progess);
#endif
if (status)
{
rb->splash(HZ*2, true, "decode error %d", status);
return NULL;
}
time = *rb->current_tick - time;
rb->snprintf(print, sizeof(print), " %d.%02d sec ", time/HZ, time%HZ);
rb->lcd_getstringsize(print, &w, &h); /* centered in progress bar */
rb->lcd_putsxy((LCD_WIDTH - w)/2, LCD_HEIGHT - h, print);
rb->lcd_update();
return p_disp;
}
/* set the view to the given center point, limit if necessary */
void set_view (struct t_disp* p_disp, int cx, int cy)
{
int x, y;
/* plain center to available width/height */
x = cx - MIN(LCD_WIDTH, p_disp->width) / 2;
y = cy - MIN(LCD_HEIGHT, p_disp->height) / 2;
/* limit against upper image size */
x = MIN(p_disp->width - LCD_WIDTH, x);
y = MIN(p_disp->height - LCD_HEIGHT, y);
/* limit against negative side */
x = MAX(0, x);
y = MAX(0, y);
p_disp->x = x; /* set the values */
p_disp->y = y;
}
/* calculate the view center based on the bitmap position */
void get_view(struct t_disp* p_disp, int* p_cx, int* p_cy)
{
*p_cx = p_disp->x + MIN(LCD_WIDTH, p_disp->width) / 2;
*p_cy = p_disp->y + MIN(LCD_HEIGHT, p_disp->height) / 2;
}
/* load, decode, display the image */
int main(char* filename)
{
int fd;
int filesize;
int grayscales;
long graysize; // helper
unsigned char* buf_jpeg; /* compressed JPEG image */
static struct jpeg jpg; /* too large for stack */
int status;
int ds, ds_min, ds_max; /* scaling and limits */
struct t_disp* p_disp; /* currenly displayed image */
int cx, cy; /* view center */
fd = rb->open(filename, O_RDONLY);
if (fd < 0)
{
rb->splash(HZ*2, true, "fopen err");
return PLUGIN_ERROR;
}
filesize = rb->filesize(fd);
rb->memset(&disp, 0, sizeof(disp));
buf = rb->plugin_get_audio_buffer(&buf_size); /* start munching memory */
/* initialize the grayscale buffer: 32 bitplanes for 33 shades of gray. */
grayscales = gray_init(rb, buf, buf_size, false, LCD_WIDTH, LCD_HEIGHT/8,
32, &graysize) + 1;
buf += graysize;
buf_size -= graysize;
if (grayscales < 33 || buf_size <= 0)
{
rb->splash(HZ*2, true, "gray buf error");
rb->close(fd);
return PLUGIN_ERROR;
}
/* allocate JPEG buffer */
align(&buf, &buf_size, 2); /* 16 bit align */
buf_jpeg = (unsigned char*)(((int)buf + 1) & ~1);
buf += filesize;
buf_size -= filesize;
buf_root = buf; /* we can start the decompressed images behind it */
root_size = buf_size;
if (buf_size <= 0)
{
rb->splash(HZ*2, true, "out of memory");
rb->close(fd);
return PLUGIN_ERROR;
}
rb->snprintf(print, sizeof(print), "loading %d bytes", filesize);
rb->lcd_puts(0, 0, print);
rb->lcd_update();
rb->read(fd, buf_jpeg, filesize);
rb->close(fd);
rb->snprintf(print, sizeof(print), "decoding markers");
rb->lcd_puts(0, 1, print);
rb->lcd_update();
rb->memset(&jpg, 0, sizeof(jpg)); /* clear info struct */
/* process markers, unstuffing */
status = process_markers(buf_jpeg, filesize, &jpg);
if (status < 0 || (status & (DQT | SOF0)) != (DQT | SOF0))
{ /* bad format or minimum components not contained */
rb->splash(HZ*2, true, "unsupported %d", status);
return PLUGIN_ERROR;
}
if (!(status & DHT)) /* if no Huffman table present: */
default_huff_tbl(&jpg); /* use default */
build_lut(&jpg); /* derive Huffman and other lookup-tables */
rb->snprintf(print, sizeof(print), "image %d*%d", jpg.x_size, jpg.y_size);
rb->lcd_puts(0, 2, print);
rb->lcd_update();
/* check display constraint */
ds_max = max_downscale(jpg.x_size, jpg.y_size);
/* check memory constraint */
ds_min = min_downscale(jpg.x_phys, jpg.y_phys, buf_size);
if (ds_min == 0)
{
rb->splash(HZ*2, true, "too large");
return PLUGIN_ERROR;
}
ds = ds_max; /* initials setting */
cx = jpg.x_size/ds/2; /* center the view */
cy = jpg.y_size/ds/2;
do /* loop the image prepare and decoding when zoomed */
{
p_disp = get_image(&jpg, ds); /* decode or fetch from cache */
if (p_disp == NULL)
return PLUGIN_ERROR;
set_view(p_disp, cx, cy);
rb->snprintf(print, sizeof(print), "showing %d*%d",
p_disp->width, p_disp->height);
rb->lcd_puts(0, 3, print);
rb->lcd_update();
gray_ub_clear_display();
gray_ub_gray_bitmap_part(
p_disp->bitmap, p_disp->x, p_disp->y, p_disp->stride,
MAX(0, (LCD_WIDTH - p_disp->width) / 2),
MAX(0, (LCD_HEIGHT - p_disp->height) / 2),
MIN(LCD_WIDTH, p_disp->width),
MIN(LCD_HEIGHT, p_disp->height));
gray_show(true); /* switch on grayscale overlay */
/* drawing is now finished, play around with scrolling
* until you press OFF or connect USB
*/
while (1)
{
status = scroll_bmp(p_disp);
if (status == ZOOM_IN)
{
if (ds > ds_min)
{
ds /= 2; /* reduce downscaling to zoom in */
get_view(p_disp, &cx, &cy);
cx *= 2; /* prepare the position in the new image */
cy *= 2;
}
else
continue;
}
if (status == ZOOM_OUT)
{
if (ds < ds_max)
{
ds *= 2; /* increase downscaling to zoom out */
get_view(p_disp, &cx, &cy);
cx /= 2; /* prepare the position in the new image */
cy /= 2;
}
else
continue;
}
break;
}
gray_show(false); /* switch off overlay */
}
while (status != PLUGIN_OK && status != PLUGIN_USB_CONNECTED);
gray_release(); /* deinitialize */
return status;
}
/******************** Plugin entry point *********************/
enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
{
rb = api; /* copy to global api pointer */
return main((char*)parameter);
}
#endif /* #ifdef HAVE_LCD_BITMAP */
#endif /* #ifndef SIMULATOR */
Reference in a new issue View git blame Copy permalink