nihilazo
/
rockbox
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

bitmap drawing: Negate alpha channel to match alpha information format of font files. 

The comment about the format was actually incorrect. The alpha information
is now negated during conversion to native format, according to the
corrected comment.

Change-Id: Ifdb9ffdf9b55e39e64983eec2d9d60339e570bd9
This commit is contained in:
Thomas Martitz 2013-02-12 10:26:44 +01:00
parent c66a66728c
commit ca634a0ac0
2 changed files with 11 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
apps/recorder/bmp.c
View File

@ -470,8 +470,9 @@ void output_row_8_native(uint32_t row, void * row_in,
*dest = LCD_RGBPACK_LCD(r, g, b);
dest += STRIDE_MAIN(1, ctx->bm->height);
if (bm_alpha) {
/* pack alpha channel for 2 pixels into 1 byte */
unsigned alpha = qp->alpha;
/* pack alpha channel for 2 pixels into 1 byte and negate
* according to the interal alpha channel format */
uint8_t alpha = ~qp->alpha;
if (col%2)
*bm_alpha++ |= alpha&0xf0;
else

16
firmware/drivers/lcd-16bit-common.c
View File

@ -782,13 +782,14 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
/* About Rockbox' internal alpha channel format (for ALPHA_COLOR_FONT_DEPTH == 2)
*
* For each pixel, 4bit of alpha information is stored in a byte-stream,
* For each pixel, 4bit of alpha information is stored in a byte-stream,
* so two pixels are packed into one byte.
* The lower nibble is the first pixel, the upper one the second. The stride is
* horizontal. E.g row0: pixel0: byte0[0:3], pixel1: byte0[4:7], pixel2: byte1[0:3],...
* The format is independant of the internal display orientation and color
* representation, as to support the same font files on all displays.
* The values go linear from 0 (fully transparent) to 15 (fully opaque).
* The values go linear from 0 (fully opaque) to 15 (fully transparent)
* (note how this is the opposite of the alpha channel in the ARGB format).
*
* This might suggest that rows need to have an even number of pixels.
* However this is generally not the case. lcd_alpha_bitmap_part_mix() can deal
@ -935,16 +936,15 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
dmask = 0xffffffff;
drmode &= DRMODE_SOLID; /* mask out inversevid */
}
/* sourcing from an image ignore drawmode.
* Set to DRMODE_BG as we use its code path in the switch below */
if (image != NULL)
{
drmode = DRMODE_BG;
}
if (drmode == DRMODE_BG)
{
dmask = ~dmask;
}
/* Set to DRMODE_BG as we use its code path in the switch below */
if (image != NULL)
{
drmode = DRMODE_BG;
}
dst_row = FBADDR(x, y);