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Support for transparency in 32bit bitmaps on color targets.

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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

87
apps/recorder/bmp.c
View file

@ -173,6 +173,7 @@ static inline void set_rgb_union(struct uint8_rgb *dst, union rgb_union src)
dst->red = src.red;
dst->green = src.green;
dst->blue = src.blue;
dst->alpha = 0xff;
}
struct bmp_args {
@ -189,6 +190,9 @@ struct bmp_args {
int cur_col;
struct img_part part;
#endif
/* as read_part_line() goes through the rows it'll set this to true
* if it finds transparency. Initialize to false before calling */
bool alpha_detected;
};
static unsigned int read_part_line(struct bmp_args *ba)
@ -233,6 +237,7 @@ static unsigned int read_part_line(struct bmp_args *ba)
#endif
return 0;
}
while (ibuf < ba->buf + (BM_MAX_WIDTH << 2))
{
switch (depth)
@ -274,6 +279,7 @@ static unsigned int read_part_line(struct bmp_args *ba)
component = data & 0xf8;
component |= component >> 5;
buf->red = component;
buf->alpha = 0xff;
buf++;
ibuf += 2;
break;
@ -282,13 +288,12 @@ static unsigned int read_part_line(struct bmp_args *ba)
buf->blue = *ibuf++;
buf->green = *ibuf++;
buf->red = *ibuf++;
if (depth == 32)
ibuf++;
buf->alpha = (depth == 32) ? *ibuf++ : 0xff;
if (buf->alpha != 0xff) ba->alpha_detected = true;
buf++;
break;
}
}
#if !defined(HAVE_LCD_COLOR) && \
((LCD_DEPTH > 1 || (defined(HAVE_REMOTE_LCD) && LCD_REMOTE_DEPTH > 1)) || \
defined(PLUGIN))
@ -422,41 +427,40 @@ void output_row_8_native(uint32_t row, void * row_in,
}
#endif /* LCD_PIXELFORMAT */
#elif LCD_DEPTH == 16
#if defined(LCD_STRIDEFORMAT) && LCD_STRIDEFORMAT == VERTICAL_STRIDE
/* M:Robe 500 */
(void) fb_width;
fb_data *dest = (fb_data *)ctx->bm->data + row;
/* iriver h300, colour iPods, X5 */
(void)fb_width;
fb_data *dest = STRIDE_MAIN((fb_data *)ctx->bm->data + fb_width * row,
(fb_data *)ctx->bm->data + row);
int delta = 127;
unsigned r, g, b;
unsigned r, g, b;
/* setup alpha channel buffer */
unsigned char *bm_alpha = NULL;
if (ctx->bm->alpha_offset > 0)
bm_alpha = ctx->bm->data + ctx->bm->alpha_offset;
if (bm_alpha)
bm_alpha += ctx->bm->width*row/2;
for (col = 0; col < ctx->bm->width; col++) {
if (ctx->dither)
delta = DITHERXDY(col,dy);
r = qp->red;
g = qp->green;
b = (qp++)->blue;
b = qp->blue;
r = (31 * r + (r >> 3) + delta) >> 8;
g = (63 * g + (g >> 2) + delta) >> 8;
b = (31 * b + (b >> 3) + delta) >> 8;
*dest = LCD_RGBPACK_LCD(r, g, b);
dest += ctx->bm->height;
dest += STRIDE_MAIN(1, ctx->bm->height);
if (bm_alpha) {
/* pack alpha channel for 2 pixels into 1 byte */
unsigned alpha = 255-qp->alpha;
if (col%2)
*bm_alpha++ |= alpha&0xf0;
else
*bm_alpha = alpha>>4;
}
qp++;
}
#else
/* iriver h300, colour iPods, X5 */
fb_data *dest = (fb_data *)ctx->bm->data + fb_width * row;
int delta = 127;
unsigned r, g, b;
for (col = 0; col < ctx->bm->width; col++) {
if (ctx->dither)
delta = DITHERXDY(col,dy);
r = qp->red;
g = qp->green;
b = (qp++)->blue;
r = (31 * r + (r >> 3) + delta) >> 8;
g = (63 * g + (g >> 2) + delta) >> 8;
b = (31 * b + (b >> 3) + delta) >> 8;
*dest++ = LCD_RGBPACK_LCD(r, g, b);
}
#endif
#endif /* LCD_DEPTH */
}
#endif
@ -480,6 +484,7 @@ int read_bmp_fd(int fd,
int depth, numcolors, compression, totalsize;
int ret;
bool return_size = format & FORMAT_RETURN_SIZE;
bool read_alpha = format & FORMAT_TRANSPARENT;
unsigned char *bitmap = bm->data;
struct uint8_rgb palette[256];
@ -608,8 +613,14 @@ int read_bmp_fd(int fd,
if (cformat)
totalsize = cformat->get_size(bm);
else
else {
totalsize = BM_SIZE(bm->width,bm->height,format,remote);
#ifdef HAVE_REMOTE_LCD
if (!remote)
#endif
if (depth == 32 && read_alpha) /* account for possible 4bit alpha per pixel */
totalsize += bm->width * bm->height / 2;
}
if(return_size)
{
@ -704,13 +715,21 @@ int read_bmp_fd(int fd,
memset(bitmap, 0, totalsize);
#ifdef HAVE_LCD_COLOR
if (read_alpha && depth == 32)
bm->alpha_offset = totalsize - (bm->width * bm->height / 2);
else
bm->alpha_offset = 0;
#endif
struct bmp_args ba = {
.fd = fd, .padded_width = padded_width, .read_width = read_width,
.width = src_dim.width, .depth = depth, .palette = palette,
#if (LCD_DEPTH > 1 || (defined(HAVE_REMOTE_LCD) && LCD_REMOTE_DEPTH > 1)) && \
defined(HAVE_BMP_SCALING) || defined(PLUGIN)
.cur_row = 0, .cur_col = 0, .part = {0,0}
.cur_row = 0, .cur_col = 0, .part = {0,0},
#endif
.alpha_detected = false,
};
#if (LCD_DEPTH > 1 || (defined(HAVE_REMOTE_LCD) && LCD_REMOTE_DEPTH > 1)) && \
@ -759,7 +778,6 @@ int read_bmp_fd(int fd,
return -6;
}
#endif
int row;
/* loop to read rows and put them to buffer */
for (row = rset.rowstart; row != rset.rowstop; row += rset.rowstep) {
@ -858,5 +876,14 @@ int read_bmp_fd(int fd,
}
#endif
}
#ifdef HAVE_LCD_COLOR
if (!ba.alpha_detected)
{ /* if this has an alpha channel, totalsize accounts for it as well
* subtract if no actual alpha information was found */
if (bm->alpha_offset > 0)
totalsize -= bm->width*bm->height/2;
bm->alpha_offset = 0;
}
#endif
return totalsize; /* return the used buffer size. */
}