Aegisub/aegisub/subtitles_provider_libass.cpp

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// Copyright (c) 2006-2007, Rodrigo Braz Monteiro, Evgeniy Stepanov
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:zeratul@cellosoft.com
//
///////////
// Headers
#include "subtitles_provider.h"
#include "ass_file.h"
#include "video_context.h"
#include "utils.h"
extern "C" {
#include <ass/ass.h>
}
///////////////////
// libass provider
class LibassSubtitlesProvider : public SubtitlesProvider {
private:
static ass_library_t* ass_library;
ass_renderer_t* ass_renderer;
ass_track_t* ass_track;
public:
LibassSubtitlesProvider();
~LibassSubtitlesProvider();
bool CanRaster() { return true; }
void LoadSubtitles(AssFile *subs);
void DrawSubtitles(AegiVideoFrame &dst,double time);
};
ass_library_t* LibassSubtitlesProvider::ass_library;
///////////
// Factory
class LibassSubtitlesProviderFactory : public SubtitlesProviderFactory {
public:
SubtitlesProvider *CreateProvider() { return new LibassSubtitlesProvider(); }
LibassSubtitlesProviderFactory() : SubtitlesProviderFactory(_T("libass")) {}
} registerLibass;
///////////////
// Constructor
LibassSubtitlesProvider::LibassSubtitlesProvider() {
// Initialize library
static bool first = true;
if (first) {
ass_library = ass_library_init();
if (!ass_library) throw _T("ass_library_init failed");
ass_set_fonts_dir(ass_library, "");
ass_set_extract_fonts(ass_library, 0);
ass_set_style_overrides(ass_library, NULL);
first = false;
}
// Initialize renderer
ass_track = NULL;
ass_renderer = ass_renderer_init(ass_library);
if (!ass_renderer) throw _T("ass_renderer_init failed");
ass_set_font_scale(ass_renderer, 1.);
ass_set_fonts(ass_renderer, NULL, "Sans");
}
//////////////
// Destructor
LibassSubtitlesProvider::~LibassSubtitlesProvider() {
}
//////////////////
// Load subtitles
void LibassSubtitlesProvider::LoadSubtitles(AssFile *subs) {
// Prepare subtitles
std::vector<char> data;
subs->SaveMemory(data,_T("UTF-8"));
delete subs;
// Load file
if (ass_track) ass_free_track(ass_track);
ass_track = ass_read_memory(ass_library, &data[3], data.size()-3,"UTF-8"); // Starting at 3 to avoid BOM
if (!ass_track) throw _T("libass failed to load subtitles.");
}
/////////////////////////////
// Macros to get the colours
#define _r(c) ((c)>>24)
#define _g(c) (((c)>>16)&0xFF)
#define _b(c) (((c)>>8)&0xFF)
#define _a(c) ((c)&0xFF)
//////////////////
// Draw subtitles
void LibassSubtitlesProvider::DrawSubtitles(AegiVideoFrame &frame,double time) {
// Set size
ass_set_frame_size(ass_renderer, frame.w, frame.h);
// Get frame
ass_image_t* img = ass_render_frame(ass_renderer, ass_track, int(time * 1000), NULL);
// libass actually returns several alpha-masked monochrome images.
// Here, we loop through their linked list, get the colour of the current, and blend into the frame.
// This is repeated for all of them.
while (img) {
// Get colours
unsigned int opacity = 255 - ((unsigned int)_a(img->color));
unsigned int r = (unsigned int)_r(img->color);
unsigned int g = (unsigned int)_g(img->color);
unsigned int b = (unsigned int) _b(img->color);
// Prepare copy
int src_stride = img->stride;
int dst_stride = frame.pitch[0];
int dst_delta = dst_stride - img->w*4;
//int stride = MIN(src_stride,dst_stride);
const unsigned char *src = img->bitmap;
unsigned char *dst = frame.data[0] + (img->dst_y * dst_stride + img->dst_x * 4);
unsigned int k,ck,t;
// Copy image to destination frame
for (int y=0;y<img->h;y++) {
//memcpy(dst,src,stride);
for (int x = 0; x < img->w; ++x) {
k = ((unsigned)src[x]) * opacity / 255;
ck = 255 - k;
t = *dst;
*dst++ = (k*b + ck*t) / 255;
t = *dst;
*dst++ = (k*g + ck*t) / 255;
t = *dst;
*dst++ = (k*r + ck*t) / 255;
dst++;
}
dst += dst_delta;
src += src_stride;
}
// Next image
img = img->next;
}
}