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Correct pixel size in the framebuffer #162

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Merged
jserv merged 3 commits into from
Apr 26, 2026
Merged

Correct pixel size in the framebuffer #162

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473b0e2
Correct pixel size for RGB565 mode
rota1001 Apr 26, 2026
6ec4c63
Correct pixel size for RGB888
rota1001 Apr 26, 2026
b081228
Drop duplicated is_argb32 and is_rgb888
rota1001 Apr 26, 2026
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70 changes: 32 additions & 38 deletions backend/fbdev.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,35 +45,40 @@ typedef struct {
} twin_fbdev_t;

/* color conversion */
#define ARGB32_TO_RGB565_PERLINE(dest, pixels, width) \
do { \
for (int i = 0; i < width; i++) \
dest[i] = ((pixels[i] & 0x00f80000) >> 8) | \
((pixels[i] & 0x0000fc00) >> 5) | \
((pixels[i] & 0x000000f8) >> 3); \
#define ARGB32_TO_RGB565_PERLINE(dest, pixels, width) \
do { \
uint16_t *_dest = (uint16_t *) dest; \
for (int i = 0; i < width; i++) \
_dest[i] = ((pixels[i] & 0x00f80000) >> 8) | \
((pixels[i] & 0x0000fc00) >> 5) | \
((pixels[i] & 0x000000f8) >> 3); \
} while (0)

/* Requires validation in 24-bit per pixel environments */
#define ARGB32_TO_RGB888_PERLINE(dest, pixels, width) \
do { \
for (int i = 0; i < width; i++) \
dest[i] = 0xff000000 | pixels[i]; \
#define ARGB32_TO_RGB888_PERLINE(dest, pixels, width) \
do { \
uint8_t *_dest = (uint8_t *) dest; \
for (int i = 0; i < width; i++) { \
_dest[i * 3] = pixels[i] & 0xFF; \
_dest[i * 3 + 1] = ((pixels[i] & 0x0000FF00) >> 8); \
_dest[i * 3 + 2] = ((pixels[i] & 0x00FF0000) >> 16); \
} \
} while (0)

#define ARGB32_TO_ARGB32_PERLINE(dest, pixels, width) \
memcpy(dest, pixels, width * sizeof(*dest))

#define FBDEV_PUT_SPAN_IMPL(bpp, op) \
static void _twin_fbdev_put_span##bpp( \
twin_coord_t left, twin_coord_t top, twin_coord_t right, \
twin_argb32_t *pixels, void *closure) \
{ \
uint32_t *dest; \
twin_fbdev_t *tx = PRIV(closure); \
off_t off = sizeof(*dest) * left + top * tx->fb_fix.line_length; \
dest = (uint32_t *) ((uintptr_t) tx->fb_base + off); \
twin_coord_t width = right - left; \
op(dest, pixels, width); \
memcpy((uint32_t *) dest, pixels, width * 4)

#define FBDEV_PUT_SPAN_IMPL(bpp, op) \
static void _twin_fbdev_put_span##bpp( \
twin_coord_t left, twin_coord_t top, twin_coord_t right, \
twin_argb32_t *pixels, void *closure) \
{ \
uintptr_t dest; \
twin_fbdev_t *tx = PRIV(closure); \
off_t off = (bpp / 8) * left + top * tx->fb_fix.line_length; \
dest = (uintptr_t) tx->fb_base + off; \
twin_coord_t width = right - left; \
op(dest, pixels, width); \
}

FBDEV_PUT_SPAN_IMPL(16, ARGB32_TO_RGB565_PERLINE)
Expand All @@ -97,14 +102,7 @@ static inline bool twin_fbdev_is_rgb565(twin_fbdev_t *tx)
tx->fb_var.blue.offset == 0 && tx->fb_var.blue.length == 5;
}

static inline bool twin_fbdev_is_rgb888(twin_fbdev_t *tx)
{
return tx->fb_var.red.offset == 16 && tx->fb_var.red.length == 8 &&
tx->fb_var.green.offset == 8 && tx->fb_var.green.length == 8 &&
tx->fb_var.blue.offset == 0 && tx->fb_var.blue.length == 8;
}

static inline bool twin_fbdev_is_argb32(twin_fbdev_t *tx)
static inline bool twin_fbdev_is_rgb888_or_argb32(twin_fbdev_t *tx)
{
return tx->fb_var.red.offset == 16 && tx->fb_var.red.length == 8 &&
tx->fb_var.green.offset == 8 && tx->fb_var.green.length == 8 &&
Expand Down Expand Up @@ -142,14 +140,10 @@ static bool twin_fbdev_apply_config(twin_fbdev_t *tx)
}
break;
case 24: /* RGB888 */
if (!twin_fbdev_is_rgb888(tx)) {
log_error("Invalid framebuffer format for 24 bpp");
return false;
}
break;
case 32: /* ARGB32 */
if (!twin_fbdev_is_argb32(tx)) {
log_error("Invalid framebuffer format for 32 bpp");
if (!twin_fbdev_is_rgb888_or_argb32(tx)) {
log_error("Invalid framebuffer format for %u bpp",
tx->fb_var.bits_per_pixel);
return false;
}
break;
Expand Down