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Support for transparency in 32bit bitmaps on color targets.

Browse source 
This uses the alpha blending capabilities introduced with anti-aliased fonts
to draw bitmaps with transparency information. The bmp loader is extended to read
this information (pass FORMAT_TRANSPARENT in format). The alpha information will
be used when drawing the bitmap.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30937 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thomas Martitz 2011-11-08 21:36:49 +00:00
parent 13209604c1
commit f443e7bbf7
4 changed files with 109 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

58
firmware/drivers/lcd-16bit-common.c
View file

@ -229,7 +229,6 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
lcd_mono_bitmap_part(src, 0, 0, width, x, y, width, height);
}
/* draw alpha bitmap for anti-alias font */
#define ALPHA_COLOR_FONT_DEPTH 2
#define ALPHA_COLOR_LOOKUP_SHIFT (1 << ALPHA_COLOR_FONT_DEPTH)
#define ALPHA_COLOR_LOOKUP_SIZE ((1 << ALPHA_COLOR_LOOKUP_SHIFT) - 1)
@ -285,11 +284,17 @@ static inline unsigned blend_color(unsigned c, unsigned a)
return blend_two_colors(c, current_vp->fg_pattern, a);
}
void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
int src_y, int stride, int x, int y,
int width, int height)
/* Blend an image with an alpha channel
* if image is NULL, drawing will happen according to the drawmode
* src is the alpha channel (4bit per pixel) */
static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
const unsigned char *src, int src_x,
int src_y, int x, int y,
int width, int height,
int stride_image, int stride_src)
{
fb_data *dst, *dst_row;
const fb_data *image_row;
unsigned dmask = 0x00000000;
int drmode = current_vp->drawmode;
/* nothing to draw? */
@ -356,13 +361,22 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
{
dmask = ~dmask;
}
/* sourcing from an image ignore drawmode.
* Set to DRMODE_BG as we use its code path in the switch below */
if (image != NULL)
{
dmask = 0;
drmode = DRMODE_BG;
}
dst_row = LCDADDR(x, y);
int col, row = height;
unsigned data, pixels;
unsigned skip_end = (stride - width);
unsigned skip_start = src_y * stride + src_x;
unsigned skip_end = (stride_src - width);
unsigned skip_start = src_y * stride_src + src_x;
unsigned skip_start_image = STRIDE_MAIN(src_y * stride_image + src_x,
src_x * stride_image + src_y);
#ifdef ALPHA_BITMAP_READ_WORDS
uint32_t *src_w = (uint32_t *)((uintptr_t)src & ~3);
@ -379,6 +393,9 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
#ifdef ALPHA_BITMAP_READ_WORDS
pixels = 8 - pixels;
#endif
if (image)
image += skip_start_image;
image_row = image;
/* go through the rows and update each pixel */
do
@ -386,6 +403,12 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
col = width;
dst = dst_row;
dst_row += ROW_INC;
if (image_row) {
image = image_row;
image_row += STRIDE_MAIN(stride_image,1);
}
else
image = dst;
#ifdef ALPHA_BITMAP_READ_WORDS
#define UPDATE_SRC_ALPHA do { \
if (--pixels) \
@ -431,10 +454,11 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
uintptr_t bo = lcd_backdrop_offset;
do
{
*dst = blend_two_colors(*dst, *(fb_data *)((uintptr_t)dst + bo),
data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*(fb_data *)((uintptr_t)dst + bo),
*image, data & ALPHA_COLOR_LOOKUP_SIZE );
dst += COL_INC;
image += STRIDE_MAIN(1, stride_image);
UPDATE_SRC_ALPHA;
}
while (--col);
@ -443,9 +467,10 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
{
do
{
*dst = blend_two_colors(*dst, current_vp->bg_pattern,
data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(current_vp->bg_pattern,
*image, data & ALPHA_COLOR_LOOKUP_SIZE );
dst += COL_INC;
image += STRIDE_MAIN(1, stride_image);
UPDATE_SRC_ALPHA;
}
while (--col);
@ -516,6 +541,15 @@ void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
} while (--row);
}
/* draw alpha bitmap for anti-alias font */
void ICODE_ATTR lcd_alpha_bitmap_part(const unsigned char *src, int src_x,
int src_y, int stride, int x, int y,
int width, int height)
{
lcd_alpha_bitmap_part_mix(NULL, src, src_x, src_y, x, y, width, height, 0, stride);
}
/* Draw a partial bitmap (mono or native) including alpha channel */
void ICODE_ATTR lcd_bmp_part(const struct bitmap* bm, int src_x, int src_y,
int x, int y, int width, int height)
@ -523,6 +557,10 @@ void ICODE_ATTR lcd_bmp_part(const struct bitmap* bm, int src_x, int src_y,
int bitmap_stride = STRIDE_MAIN(bm->width, bm->height);
if (bm->format == FORMAT_MONO)
lcd_mono_bitmap_part(bm->data, src_x, src_y, bitmap_stride, x, y, width, height);
else if (bm->alpha_offset > 0)
lcd_alpha_bitmap_part_mix((fb_data*)bm->data, bm->data+bm->alpha_offset,
src_x, src_y, x, y, width, height,
bitmap_stride, bm->width);
else
lcd_bitmap_transparent_part((fb_data*)bm->data,
src_x, src_y, bitmap_stride, x, y, width, height);

3
firmware/export/lcd.h
View file

@ -467,6 +467,9 @@ struct bitmap {
#if (LCD_DEPTH > 1) || defined(HAVE_REMOTE_LCD) && (LCD_REMOTE_DEPTH > 1)
int format;
unsigned char *maskdata;
#endif
#ifdef HAVE_LCD_COLOR
int alpha_offset; /* byte-offset of alpha channel in data */
#endif
unsigned char *data;
};