webp: intial support for WebP images, using libwebp

1 files changed, 73 insertions, 0 deletions

diff --git a/webp.c b/webp.c
new file mode 100644
index 0000000..82aa493
--- /dev/null
+++ b/webp.c
@@ -0,0 +1,73 @@
+#include "webp.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <webp/decode.h>
+
+#define LOG_MODULE "webp"
+#define LOG_ENABLE_DBG 0
+#include "log.h"
+#include "stride.h"
+
+pixman_image_t *
+webp_load(FILE *fp, const char *path)
+{
+    uint8_t *file_data = NULL;
+    uint8_t *image_data = NULL;
+    size_t image_size;
+    pixman_image_t *pix = NULL;
+    pixman_format_code_t format;
+    int width, height, stride;
+
+    if (fseek(fp, 0, SEEK_END) < 0) {
+        LOG_ERRNO("%s: failed to seek to end of file", path);
+        return NULL;
+    }
+    image_size = ftell(fp);
+    if (fseek(fp, 0, SEEK_SET) < 0) {
+        LOG_ERRNO("%s: failed to seek to beginning of file", path);
+        return NULL;
+    }
+
+    if (!(file_data = WebPMalloc(image_size + 1))) {
+        goto err;
+    }
+
+    clearerr(fp);
+    fread(file_data, image_size, 1, fp);
+    if (ferror(fp)) {
+        LOG_ERRNO("%s: failed to read", path);
+        goto err;
+    }
+    file_data[image_size] = '\0';
+
+    /* Verify it is a webp image */
+    if (!WebPGetInfo(file_data, image_size, NULL, NULL)) {
+        LOG_ERR("%s: not a WebP file", path);
+        goto err;
+    }
+
+    image_data = WebPDecodeRGBA(file_data, image_size, &width, &height);
+    if (image_data == NULL) {
+        goto err;
+    }
+    format = PIXMAN_x8b8g8r8;
+    stride = stride_for_format_and_width(format, width);
+
+    pix = pixman_image_create_bits_no_clear(
+        format, width, height, (uint32_t *)image_data, stride);
+
+    if (pix == NULL) {
+        LOG_ERR("%s: failed to instantiate pixman image", path);
+        goto err;
+    }
+
+    WebPFree(file_data);
+    return pix;
+
+err:
+    WebPFree(file_data);
+    WebPFree(image_data);
+
+    return NULL;
+}