diff options
Diffstat (limited to 'desktop/bitmap.c')
| -rw-r--r-- | desktop/bitmap.c | 174 |
1 files changed, 160 insertions, 14 deletions
diff --git a/desktop/bitmap.c b/desktop/bitmap.c index a78057631..d14dd370c 100644 --- a/desktop/bitmap.c +++ b/desktop/bitmap.c @@ -96,21 +96,25 @@ void bitmap_set_format(const bitmap_fmt_t *bitmap_format) bitmap_layout = bitmap__get_colour_layout(&bitmap_fmt); } -/* Exported function, documented in desktop/bitmap.h */ -void bitmap_format_convert(void *bitmap, - const bitmap_fmt_t *fmt_from, - const bitmap_fmt_t *fmt_to) +/** + * Swap colour component order. + * + * \param[in] width Bitmap width in pixels. + * \param[in] height Bitmap height in pixels. + * \param[in] buffer Pixel buffer. + * \param[in] rowstride Pixel buffer row stride in bytes. + * \param[in] to Pixel layout to convert to. + * \param[in] from Pixel layout to convert from. + */ +static inline void bitmap__format_convert( + int width, + int height, + uint8_t *buffer, + size_t rowstride, + struct bitmap_colour_layout to, + struct bitmap_colour_layout from) { - int width = guit->bitmap->get_width(bitmap); - int height = guit->bitmap->get_height(bitmap); - uint8_t *buffer = guit->bitmap->get_buffer(bitmap); - size_t rowstride = guit->bitmap->get_rowstride(bitmap); - struct bitmap_colour_layout to = bitmap__get_colour_layout(fmt_to); - struct bitmap_colour_layout from = bitmap__get_colour_layout(fmt_from); - - NSLOG(netsurf, DEEPDEBUG, "Bitmap format conversion (%u --> %u)", - fmt_from->layout, fmt_to->layout); - + /* Just swapping the components around */ for (int y = 0; y < height; y++) { uint8_t *row = buffer; @@ -128,3 +132,145 @@ void bitmap_format_convert(void *bitmap, buffer += rowstride; } } + +/** + * Convert plain alpha to premultiplied alpha. + * + * \param[in] width Bitmap width in pixels. + * \param[in] height Bitmap height in pixels. + * \param[in] buffer Pixel buffer. + * \param[in] rowstride Pixel buffer row stride in bytes. + * \param[in] to Pixel layout to convert to. + * \param[in] from Pixel layout to convert from. + */ +static inline void bitmap__format_convert_to_pma( + int width, + int height, + uint8_t *buffer, + size_t rowstride, + struct bitmap_colour_layout to, + struct bitmap_colour_layout from) +{ + for (int y = 0; y < height; y++) { + uint8_t *row = buffer; + + for (int x = 0; x < width; x++) { + const uint32_t px = *((uint32_t *)(void *) row); + uint32_t a, r, g, b; + + r = ((const uint8_t *) &px)[from.r]; + g = ((const uint8_t *) &px)[from.g]; + b = ((const uint8_t *) &px)[from.b]; + a = ((const uint8_t *) &px)[from.a]; + + if (a != 0) { + r = ((r * (a + 1)) >> 8) & 0xff; + g = ((g * (a + 1)) >> 8) & 0xff; + b = ((b * (a + 1)) >> 8) & 0xff; + } else { + r = g = b = 0; + } + + row[to.r] = r; + row[to.g] = g; + row[to.b] = b; + row[to.a] = a; + + row += sizeof(uint32_t); + } + + buffer += rowstride; + } +} + +/** + * Convert from premultiplied alpha to plain alpha. + * + * \param[in] width Bitmap width in pixels. + * \param[in] height Bitmap height in pixels. + * \param[in] buffer Pixel buffer. + * \param[in] rowstride Pixel buffer row stride in bytes. + * \param[in] to Pixel layout to convert to. + * \param[in] from Pixel layout to convert from. + */ +static inline void bitmap__format_convert_from_pma( + int width, + int height, + uint8_t *buffer, + size_t rowstride, + struct bitmap_colour_layout to, + struct bitmap_colour_layout from) +{ + for (int y = 0; y < height; y++) { + uint8_t *row = buffer; + + for (int x = 0; x < width; x++) { + const uint32_t px = *((uint32_t *)(void *) row); + uint32_t a, r, g, b; + + r = ((const uint8_t *) &px)[from.r]; + g = ((const uint8_t *) &px)[from.g]; + b = ((const uint8_t *) &px)[from.b]; + a = ((const uint8_t *) &px)[from.a]; + + if (a != 0) { + r = (r << 8) / a; + g = (g << 8) / a; + b = (b << 8) / a; + + r = (r > 255) ? 255 : r; + g = (g > 255) ? 255 : g; + b = (b > 255) ? 255 : b; + } else { + r = g = b = 0; + } + + row[to.r] = r; + row[to.g] = g; + row[to.b] = b; + row[to.a] = a; + + row += sizeof(uint32_t); + } + + buffer += rowstride; + } +} + +/* Exported function, documented in desktop/bitmap.h */ +void bitmap_format_convert(void *bitmap, + const bitmap_fmt_t *fmt_from, + const bitmap_fmt_t *fmt_to) +{ + int width = guit->bitmap->get_width(bitmap); + int height = guit->bitmap->get_height(bitmap); + bool opaque = guit->bitmap->get_opaque(bitmap); + uint8_t *buffer = guit->bitmap->get_buffer(bitmap); + size_t rowstride = guit->bitmap->get_rowstride(bitmap); + struct bitmap_colour_layout to = bitmap__get_colour_layout(fmt_to); + struct bitmap_colour_layout from = bitmap__get_colour_layout(fmt_from); + + NSLOG(netsurf, DEEPDEBUG, "%p: format conversion (%u%s --> %u%s)", + bitmap, + fmt_from->layout, fmt_from->pma ? " pma" : "", + fmt_to->layout, fmt_to->pma ? " pma" : ""); + + if (fmt_from->pma == fmt_to->pma) { + /* Just component order to switch. */ + bitmap__format_convert( + width, height, buffer, + rowstride, to, from); + + } else if (opaque == false) { + /* Need to do conversion to/from premultiplied alpha. */ + if (fmt_to->pma) { + bitmap__format_convert_to_pma( + width, height, buffer, + rowstride, to, from); + } else { + bitmap__format_convert_from_pma( + width, height, buffer, + rowstride, to, from); + } + } +} |