1 files changed, 124 insertions, 0 deletions
diff --git a/desktop/bitmap.h b/desktop/bitmap.h
new file mode 100644
index 000000000..490928980
--- /dev/null
+++ b/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