imgproxy/testutil/image_hash_matcher.c

#include "image_hash_matcher.h"

/**
 * vips_image_read_to_memory: converts VipsImage to RGBA format and reads into memory buffer
 * @in: VipsImage to convert and read
 * @buf: pointer to buffer pointer (will be allocated)
 * @size: pointer to size_t to store the buffer size
 *
 * Converts the VipsImage to RGBA format using VIPS operations and reads the raw pixel data.
 * The caller is responsible for freeing the buffer using vips_memory_buffer_free().
 *
 * Returns: 0 on success, -1 on error
 */
int
vips_image_read_from_to_memory(void *in, size_t in_size, void **out, size_t *out_size, int *out_width, int *out_height)
{
  if (!in || !out || !out_size || !out_width || !out_height) {
    vips_error("vips_image_read_from_to_memory", "invalid arguments");
    return -1;
  }

  VipsImage *base = vips_image_new_from_buffer(in, in_size, "", NULL);
  if (base == NULL) {
    return -1;
  }

  // NOTE: Looks like there is a vips bug: if there were errors during format detection,
  // they would be saved in vips error buffer. However, if format detection was successful,
  // we expect that error buffer should be empty.
  // vips_error_clear();

  VipsImage **t = (VipsImage **) vips_object_local_array(VIPS_OBJECT(base), 2);

  // Initialize output parameters
  *out = NULL;
  *out_size = 0;

  // Convert to sRGB colorspace first if needed
  if (vips_colourspace(base, &t[0], VIPS_INTERPRETATION_sRGB, NULL) != 0) {
    VIPS_UNREF(base);
    vips_error("vips_image_read_from_to_memory", "failed to convert to sRGB");
    return -1;
  }

  in = t[0];

  // Add alpha channel if not present (convert to RGBA)
  if (!vips_image_hasalpha(base)) {
    // Add alpha channel
    if (vips_addalpha(base, &t[1], NULL) != 0) {
      VIPS_UNREF(base);
      vips_error("vips_image_read_from_to_memory", "failed to add alpha channel");
      return -1;
    }
    in = t[1];
  }

  // Get raw pixel data, width and height
  *out = vips_image_write_to_memory(in, out_size);
  *out_width = base->Xsize;
  *out_height = base->Ysize;

  // Dispose the image regardless of the result
  VIPS_UNREF(base);

  if (*out == NULL) {
    vips_error("vips_image_read_from_to_memory", "failed to write image to memory");
    return -1;
  }

  return 0;
}

/**
 * vips_memory_buffer_free: frees memory buffer allocated by vips_image_write_to_memory
 * @buf: buffer pointer to free
 *
 * Frees the memory buffer allocated by vips_image_write_to_memory.
 * Safe to call with NULL pointer.
 */
void
vips_memory_buffer_free(void *buf)
{
  if (buf) {
    g_free(buf);
  }
}