remove unneeded LCD_DEPTH test in lib/resize.h, add some comments explaining the core-file imports

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19715 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/lib/SOURCES

@@ -4,6 +4,10 @@ fixedpoint.c
 playback_control.c
 rgb_hsv.c
 #if defined(HAVE_LCD_BITMAP) && (LCD_DEPTH < 4)
+/*
+   The scaler is not provided in core on mono targets, but is built in
+   pluginlib for use with greylib overlay output
+*/
 #if LCD_DEPTH == 1
 resize.c
 #endif

apps/plugins/lib/bmp.c

@@ -27,7 +27,7 @@
 #include "lcd.h"
 #include "system.h"
 
-#if LCD_DEPTH > 1
+#if LCD_DEPTH > 1  /* save is only available for color, resize for >1bpp */
 #ifdef HAVE_LCD_COLOR
 #define LE16(x) (htole16(x))&0xff, ((htole16(x))>>8)&0xff
 #define LE32(x) (htole32(x))&0xff, ((htole32(x))>>8)&0xff, ((htole32(x))>>16)&0xff, ((htole32(x))>>24)&0xff
@@ -122,13 +122,15 @@ void simple_resize_bitmap(struct bitmap *src, struct bitmap *dst)
     }
 }
 
-#else
+#else /* LCD_DEPTH == 1 */
 #include "wrappers.h"
 
 static const struct plugin_api *rb;
 
+/* import the core bmp loader */
 #include "../../recorder/bmp.c"
 
+/* initialize rb for use by the bmp loader */
 void bmp_init(const struct plugin_api *api)
 {
     rb = api;

apps/plugins/lib/bmp.h

@@ -24,7 +24,7 @@
 #include "lcd.h"
 #include "plugin.h"
 
-#if LCD_DEPTH > 1
+#if LCD_DEPTH > 1 /* save is only available for color, resize for >1bpp */
 #ifdef HAVE_LCD_COLOR
 /**
  * Save bitmap to file
@@ -45,6 +45,11 @@ void simple_resize_bitmap(struct bitmap *src, struct bitmap *dst);
 void smooth_resize_bitmap(struct bitmap *src,  struct bitmap *dst);
 
 #else
+/*
+   BMP loader is built with scaling support in pluginlib on 1bpp targets, as
+   these do not provide scaling support in the core BMP loader. bmp_init is
+   needed to copy the plugin API pointer for the pluginlib loader's use.
+*/
 void bmp_init(const struct plugin_api *api);
 #endif
 

apps/plugins/lib/resize.h

@@ -24,8 +24,6 @@
 #ifndef _LIB_RESIZE_H_
 #define _LIB_RESIZE_H_
 
-#if LCD_DEPTH == 1
 void resize_init(const struct plugin_api *api);
-#endif
 
 #endif