gvdevice_webp.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include "config.h"
 
#include <gvc/gvplugin_device.h>
#include <gvc/gvio.h>
 
#ifdef HAVE_WEBP
#include "webp/encode.h"
 
static const char* const kErrorMessages[] = {
    "OK",
    "OUT_OF_MEMORY: Out of memory allocating objects",
    "BITSTREAM_OUT_OF_MEMORY: Out of memory re-allocating byte buffer",
    "NULL_PARAMETER: NULL parameter passed to function",
    "INVALID_CONFIGURATION: configuration is invalid",
    "BAD_DIMENSION: Bad picture dimension. Maximum width and height "
        "allowed is 16383 pixels.",
    "PARTITION0_OVERFLOW: Partition #0 is too big to fit 512k.\n"
        "To reduce the size of this partition, try using less segments "
        "with the -segments option, and eventually reduce the number of "
        "header bits using -partition_limit. More details are available "
        "in the manual (`man cwebp`)",
    "PARTITION_OVERFLOW: Partition is too big to fit 16M",
    "BAD_WRITE: Picture writer returned an I/O error",
    "FILE_TOO_BIG: File would be too big to fit in 4G",
    "USER_ABORT: encoding abort requested by user"
};
 
typedef enum {
    FORMAT_WEBP,
} format_type;
 
static int writer(const uint8_t* data, size_t data_size, const WebPPicture* const pic) {
    return gvwrite(pic->custom_ptr, (const char *)data, data_size) == data_size ? 1 : 0;
}
 
static void webp_format(GVJ_t * job)
{
    WebPPicture picture;
    WebPPreset preset;
    WebPConfig config;
    int stride;
 
    if (!WebPPictureInit(&picture) || !WebPConfigInit(&config)) {
        fprintf(stderr, "Error! Version mismatch!\n");
        goto Error;
    }
 
    // if either dimension exceeds the WebP API, map this to one of its errors
    if ((unsigned)INT_MAX / 4 < job->width || job->height > (unsigned)INT_MAX) {
        int error = VP8_ENC_ERROR_BAD_DIMENSION;
        fprintf(stderr, "Error! Cannot encode picture as WebP\n");
        fprintf(stderr, "Error code: %d (%s)\n", error, kErrorMessages[error]);
        goto Error;
    }
 
    picture.width = (int)job->width;
    picture.height = (int)job->height;
    stride = 4 * (int)job->width;
 
    picture.writer = writer;
    picture.custom_ptr = job;
 
    preset = WEBP_PRESET_DRAWING;
 
    if (!WebPConfigPreset(&config, preset, config.quality)) {
        fprintf(stderr, "Error! Could initialize configuration with preset.\n");
        goto Error;
    }
 
    if (!WebPValidateConfig(&config)) {
        fprintf(stderr, "Error! Invalid configuration.\n");
        goto Error;
    }
 
    if (!WebPPictureAlloc(&picture)) {
        fprintf(stderr, "Error! Cannot allocate memory\n");
        return;
    }
 
    if (!WebPPictureImportBGRA(&picture, job->imagedata, stride)) {
        fprintf(stderr, "Error! Cannot import picture\n");
        goto Error;
    }
 
    if (!WebPEncode(&config, &picture)) {
        fprintf(stderr, "Error! Cannot encode picture as WebP\n");
        fprintf(stderr, "Error code: %d (%s)\n",
            picture.error_code, kErrorMessages[picture.error_code]);
        goto Error;
     }
 
Error:
     WebPPictureFree(&picture);
}
 
static gvdevice_engine_t webp_engine = {
    NULL,               /* webp_initialize */
    webp_format,
    NULL,               /* webp_finalize */
};
 
static gvdevice_features_t device_features_webp = {
        GVDEVICE_BINARY_FORMAT        
          | GVDEVICE_NO_WRITER
          | GVDEVICE_DOES_TRUECOLOR,/* flags */
        {0.,0.},                    /* default margin - points */
        {0.,0.},                    /* default page width, height - points */
        {96.,96.},                  /* 96 dpi */
};
#endif
 
gvplugin_installed_t gvdevice_webp_types[] = {
#ifdef HAVE_WEBP
    {FORMAT_WEBP, "webp:cairo", 1, &webp_engine, &device_features_webp},
#endif
    {0, NULL, 0, NULL, NULL}
};