Include: Bitmap: Add API for setting core bitmap format.

desktop/Makefile

@@ -12,7 +12,7 @@ desktop/version.c: testament $(OBJROOT)/testament.h
 
 # S_BROWSER are sources related to full browsers but are common
 # between RISC OS, GTK, BeOS and AmigaOS builds
-S_BROWSER := browser.c browser_window.c browser_history.c \
+S_BROWSER := bitmap.c browser.c browser_window.c browser_history.c \
 	download.c frames.c netsurf.c cw_helper.c \
 	save_complete.c save_text.c selection.c textinput.c gui_factory.c \
 	save_pdf.c font_haru.c

desktop/bitmap.c

@@ -0,0 +1,46 @@
+/*
+ * 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;
+
+/* Exported function, documented in include/netsurf/bitmap.h */
+void bitmap_set_format(const bitmap_fmt_t *bitmap_format)
+{
+	bitmap_fmt = *bitmap_format;
+
+	bitmap_fmt.layout = bitmap_sanitise_bitmap_layout(bitmap_fmt.layout);
+	bitmap_layout = bitmap__get_colour_layout(&bitmap_fmt);
+}

desktop/bitmap.h

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2022 Michael Drake <tlsa@nesturf-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.
+ */
+
+#ifndef _NETSURF_DESKTOP_BITMAP_H_
+#define _NETSURF_DESKTOP_BITMAP_H_
+
+#include <nsutils/endian.h>
+
+#include "netsurf/bitmap.h"
+
+/** The client bitmap format. */
+extern bitmap_fmt_t bitmap_fmt;
+
+/** Pixel format: colour component order. */
+struct bitmap_colour_layout {
+	uint8_t r; /**< Byte offset within pixel to red component. */
+	uint8_t g; /**< Byte offset within pixel to green component. */
+	uint8_t b; /**< Byte offset within pixel to blue component. */
+	uint8_t a; /**< Byte offset within pixel to alpha component. */
+};
+
+/**
+ * Get the colour layout for the given bitmap format.
+ *
+ * \param[in] fmt  Pixel format to get channel layout for,
+ * \return channel layout structure.
+ */
+static inline 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,
+		};
+	}
+}
+
+/**
+ * Sanitise bitmap pixel component layout.
+ *
+ * Map endian-dependant layouts to byte-wise layout for the host.
+ *
+ * \param[in]  layout  Layout to convert.
+ * \return sanitised layout.
+ */
+static inline enum bitmap_layout bitmap_sanitise_bitmap_layout(
+		enum bitmap_layout layout)
+{
+	bool le = endian_host_is_le();
+
+	switch (layout) {
+	case BITMAP_LAYOUT_RGBA8888:
+		layout = (le) ? BITMAP_LAYOUT_A8B8G8R8
+		              : BITMAP_LAYOUT_R8G8B8A8;
+		break;
+	case BITMAP_LAYOUT_BGRA8888:
+		layout = (le) ? BITMAP_LAYOUT_A8R8G8B8
+		              : BITMAP_LAYOUT_B8G8R8A8;
+		break;
+	case BITMAP_LAYOUT_ARGB8888:
+		layout = (le) ? BITMAP_LAYOUT_B8G8R8A8
+		              : BITMAP_LAYOUT_A8R8G8B8;
+		break;
+	case BITMAP_LAYOUT_ABGR8888:
+		layout = (le) ? BITMAP_LAYOUT_R8G8B8A8
+		              : BITMAP_LAYOUT_A8B8G8R8;
+		break;
+	default:
+		break;
+	}
+
+	return layout;
+}
+
+#endif

include/netsurf/bitmap.h

@@ -61,10 +61,77 @@ enum gui_bitmap_flags {
 	BITMAP_CLEAR  = (1 << 1), /**< memory should be wiped to 0 */
 };
 
+/**
+ * NetSurf bitmap pixel layout.
+ *
+ * All pixels are 32 bits per pixel (bpp). The different layouts allow control
+ * over the ordering of colour channels. All colour channels are 8 bits wide.
+ */
+enum bitmap_layout {
+	/** Bite-wise RGBA: Byte order: 0xRR, 0xGG, 0xBB, 0xAA. */
+	BITMAP_LAYOUT_R8G8B8A8,
+
+	/** Bite-wise BGRA: Byte order: 0xBB, 0xGG, 0xRR, 0xAA. */
+	BITMAP_LAYOUT_B8G8R8A8,
+
+	/** Bite-wise ARGB: Byte order: 0xAA, 0xRR, 0xGG, 0xBB. */
+	BITMAP_LAYOUT_A8R8G8B8,
+
+	/** Bite-wise ABGR: Byte order: 0xAA, 0xBB, 0xGG, 0xRR. */
+	BITMAP_LAYOUT_A8B8G8R8,
+
+	/**
+	 * 32-bit RGBA (0xRRGGBBAA).
+	 *
+	 * * On little endian host, same as \ref BITMAP_LAYOUT_A8B8G8R8.
+	 * * On big endian host, same as \ref BITMAP_LAYOUT_R8G8B8A8.
+	 */
+	BITMAP_LAYOUT_RGBA8888,
+
+	/**
+	 * 32-bit BGRA (0xBBGGRRAA).
+	 *
+	 * * On little endian host, same as \ref BITMAP_LAYOUT_A8R8G8B8.
+	 * * On big endian host, same as \ref BITMAP_LAYOUT_B8G8R8A8.
+	 */
+	BITMAP_LAYOUT_BGRA8888,
+
+	/**
+	 * 32-bit ARGB (0xAARRGGBB).
+	 *
+	 * * On little endian host, same as \ref BITMAP_LAYOUT_B8G8R8A8.
+	 * * On big endian host, same as \ref BITMAP_LAYOUT_A8R8G8B8.
+	 */
+	BITMAP_LAYOUT_ARGB8888,
+
+	/**
+	 * 32-bit BGRA (0xAABBGGRR).
+	 *
+	 * * On little endian host, same as \ref BITMAP_LAYOUT_R8G8B8A8.
+	 * * On big endian host, same as \ref BITMAP_LAYOUT_A8B8G8R8.
+	 */
+	BITMAP_LAYOUT_ABGR8888,
+};
+
+/** Bitmap format specifier. */
+typedef struct bitmap_fmt {
+	enum bitmap_layout layout; /** Colour component layout. */
+} bitmap_fmt_t;
+
 struct content;
 struct bitmap;
 struct hlcache_handle;
 
+/**
+ * Set client bitmap format.
+ *
+ * Set this to ensure that the bitmaps decoded by the core are in the
+ * correct format for the front end.
+ *
+ * \param[in]  bitmap_format  The bitmap format specification to set.
+ */
+void bitmap_set_format(const bitmap_fmt_t *bitmap_format);
+
 /**
  * Bitmap operations.
  */