eeshow/: add icon loader and icons for "delta" and "diff"

eeshow/gui/icons.c

@@ -0,0 +1,73 @@
+/*
+ * gui/icons.c - Icons
+ *
+ * Written 2016 by Werner Almesberger
+ * Copyright 2016 by Werner Almesberger
+ *
+ * This program 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+#include <cairo/cairo.h>
+
+#include "gui/icons.h"
+
+
+cairo_surface_t *icon_delta;
+cairo_surface_t *icon_diff;
+
+
+struct read_ctx {
+	uint8_t *data;
+	unsigned left;
+};
+
+
+static uint8_t data_delta[] = {
+#include "icons/delta.hex"
+};
+
+static uint8_t data_diff[] = {
+#include "icons/diff.hex"
+};
+
+
+static cairo_status_t read_data(void *user, unsigned char *data,
+    unsigned length)
+{
+	struct read_ctx *read_ctx = user;
+
+	if (!read_ctx->left)
+		return CAIRO_STATUS_READ_ERROR;
+	if (length > read_ctx->left)
+		length = read_ctx->left;
+	memcpy(data, read_ctx->data, length);
+	read_ctx->data += length;
+	read_ctx->left -= length;
+	return CAIRO_STATUS_SUCCESS;
+}
+
+
+static cairo_surface_t *get_icon(uint8_t *data, unsigned size)
+{
+	struct read_ctx read_ctx = {
+		.data	= data,
+		.left	= size,
+	};
+
+
+	return cairo_image_surface_create_from_png_stream(read_data, &read_ctx);
+}
+
+
+void icons_init(void)
+{
+	icon_delta = get_icon(data_delta, sizeof(data_delta));
+	icon_diff = get_icon(data_diff, sizeof(data_diff));
+
+}