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-rw-r--r--desktop/bitmap.c338
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diff --git a/desktop/bitmap.c b/desktop/bitmap.c
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+++ b/desktop/bitmap.c
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+/*
+ * Copyright 2022 Michael Drake <tlsa@netsurf-browser.org>
+ *
+ * This file is part of NetSurf, http://www.netsurf-browser.org/
+ *
+ * NetSurf is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * NetSurf is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** \file
+ * Internal core bitmap interface.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "utils/log.h"
+#include "utils/errors.h"
+
+#include "desktop/bitmap.h"
+#include "desktop/gui_internal.h"
+
+/** The client bitmap format. */
+bitmap_fmt_t bitmap_fmt;
+
+/** The client bitmap colour channel layout. */
+struct bitmap_colour_layout bitmap_layout = {
+ .r = 0,
+ .g = 1,
+ .b = 2,
+ .a = 3,
+};
+
+/**
+ * Get the colour layout for the given bitmap format.
+ *
+ * \param[in] fmt Pixel format to get channel layout for,
+ * \return channel layout structure.
+ */
+static struct bitmap_colour_layout bitmap__get_colour_layout(
+ const bitmap_fmt_t *fmt)
+{
+ switch (fmt->layout) {
+ default:
+ /* Fall through. */
+ case BITMAP_LAYOUT_R8G8B8A8:
+ return (struct bitmap_colour_layout) {
+ .r = 0,
+ .g = 1,
+ .b = 2,
+ .a = 3,
+ };
+
+ case BITMAP_LAYOUT_B8G8R8A8:
+ return (struct bitmap_colour_layout) {
+ .b = 0,
+ .g = 1,
+ .r = 2,
+ .a = 3,
+ };
+
+ case BITMAP_LAYOUT_A8R8G8B8:
+ return (struct bitmap_colour_layout) {
+ .a = 0,
+ .r = 1,
+ .g = 2,
+ .b = 3,
+ };
+
+ case BITMAP_LAYOUT_A8B8G8R8:
+ return (struct bitmap_colour_layout) {
+ .a = 0,
+ .b = 1,
+ .g = 2,
+ .r = 3,
+ };
+ }
+}
+
+/**
+ * Get string for given pixel layout.
+ *
+ * \param[in] layout The pixel layout to get string for,
+ * \return String for given layout.
+ */
+static const char *bitmap__layout_to_str(enum bitmap_layout layout)
+{
+ const char *const str[] = {
+ [BITMAP_LAYOUT_R8G8B8A8] = "Byte-wise RGBA",
+ [BITMAP_LAYOUT_B8G8R8A8] = "Byte-wise BGRA",
+ [BITMAP_LAYOUT_A8R8G8B8] = "Byte-wise ARGB",
+ [BITMAP_LAYOUT_A8B8G8R8] = "Byte-wise ABGR",
+ [BITMAP_LAYOUT_RGBA8888] = "0xRRGGBBAA (native endian)",
+ [BITMAP_LAYOUT_BGRA8888] = "0xBBGGRRAA (native endian)",
+ [BITMAP_LAYOUT_ARGB8888] = "0xAARRGGBB (native endian)",
+ [BITMAP_LAYOUT_ABGR8888] = "0xAABBGGRR (native endian)",
+ };
+
+ if ((size_t)layout >= (sizeof(str)) / sizeof(*str) ||
+ str[layout] == NULL) {
+ return "Unknown";
+ }
+
+ return str[layout];
+}
+
+/* Exported function, documented in include/netsurf/bitmap.h */
+void bitmap_set_format(const bitmap_fmt_t *bitmap_format)
+{
+ bitmap_fmt = *bitmap_format;
+
+ NSLOG(netsurf, INFO, "Setting core bitmap format to: %s%s",
+ bitmap__layout_to_str(bitmap_format->layout),
+ bitmap_format->pma ? " pre multiplied alpha" : "");
+
+ bitmap_fmt.layout = bitmap_sanitise_bitmap_layout(bitmap_fmt.layout);
+
+ if (bitmap_format->layout != bitmap_fmt.layout) {
+ NSLOG(netsurf, INFO, "Sanitised layout to: %s",
+ bitmap__layout_to_str(bitmap_fmt.layout));
+ }
+
+ bitmap_layout = bitmap__get_colour_layout(&bitmap_fmt);
+}
+
+/**
+ * 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)
+{
+ /* Just swapping the components around */
+ 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);
+
+ row[to.r] = ((const uint8_t *) &px)[from.r];
+ row[to.g] = ((const uint8_t *) &px)[from.g];
+ row[to.b] = ((const uint8_t *) &px)[from.b];
+ row[to.a] = ((const uint8_t *) &px)[from.a];
+
+ row += sizeof(uint32_t);
+ }
+
+ 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);
+ }
+ }
+}
+
+/* Exported function, documented in desktop/bitmap.h */
+bool bitmap_test_opaque(void *bitmap)
+{
+ int width = guit->bitmap->get_width(bitmap);
+ int height = guit->bitmap->get_height(bitmap);
+ size_t rowstride = guit->bitmap->get_rowstride(bitmap);
+ const uint8_t *buffer = guit->bitmap->get_buffer(bitmap);
+
+ width *= sizeof(uint32_t);
+
+ for (int y = 0; y < height; y++) {
+ const uint8_t *row = buffer;
+
+ for (int x = bitmap_layout.a; x < width; x += 4) {
+ if (row[x] != 0xff) {
+ return false;
+ }
+ }
+
+ buffer += rowstride;
+ }
+
+ return true;
+}
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