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'use strict';
const assert = require('chai').assert;
const Tools = require('./lib/tools');
const { Gif, GifFrame, GifCodec, GifUtil, GifError } = require('../src/index');
// compare decoded encodings with decodings intead of comparing buffers, because there are many ways to encode the same data
const defaultCodec = new GifCodec();
describe("single-frame encoding", () => {
it("encodes an opaque monochrome GIF", () => {
const name = 'singleFrameMonoOpaque';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a transparent GIF", () => {
const name = 'singleFrameNoColorTrans';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a monochrome GIF with transparency", () => {
const name = 'singleFrameMonoTrans';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a opaque two-color GIF", () => {
const name = 'singleFrameBWOpaque';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a opaque multi-color GIF", () => {
const name = 'singleFrameMultiOpaque';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a 4-color GIF w/ transparency", () => {
const name = 'singleFrameMultiTrans';
return _encodeDecodeFile(name, Gif.LocalColorsOnly); // simple code 1st
// .then(() => {
// return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
// });
});
});
describe("multi-frame encoding", () => {
it("encodes a 2-frame multi-color opaque GIF", () => {
const name = 'twoFrameMultiOpaque';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a 3-frame monocolor GIF with transparency", () => {
const name = 'threeFrameMonoTrans';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a large multiframe file w/out transparency", () => {
const name = 'nburling-public';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes a large multiframe file w/ offsets, w/out transparency", () => {
const name = 'rnaples-offsets-public';
return _encodeDecodeFile(name, Gif.LocalColorsOnly) // simple code 1st
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly);
});
});
it("encodes large multiframe files w/ forced buffer-size scaling (1)", () => {
const scalingCodec = new GifCodec();
scalingCodec._testInitialBufferSize = 2048; // big enough for header
const name = 'nburling-public';
return _encodeDecodeFile(name, Gif.LocalColorsOnly, scalingCodec)
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly, scalingCodec);
});
});
it("encodes large multiframe files w/ forced buffer-size scaling (2)", () => {
const scalingCodec = new GifCodec();
scalingCodec._testInitialBufferSize = 2048; // big enough for header
const name = 'rnaples-offsets-public';
return _encodeDecodeFile(name, Gif.LocalColorsOnly, scalingCodec)
.then(() => {
return _encodeDecodeFile(name, Gif.GlobalColorsOnly, scalingCodec);
});
});
});
describe("encoding GlobalColorsPreferred", () => {
it("uses a global color table when 256 colors in 1 frame", () => {
const frames = [];
const options = { colorScope: Gif.GlobalColorsPreferred };
frames.push(_get256ColorFrame());
return defaultCodec.encodeGif(frames, options)
.then(encodedGif => {
options.colorScope = Gif.GlobalColorsOnly;
return defaultCodec.encodeGif(frames, options);
})
.then(encodedGif => {
assert(true);
})
});
it("uses a global color table when 256 colors in each of 2 frames", () => {
const frames = [];
const options = { colorScope: Gif.GlobalColorsPreferred };
frames.push(_get256ColorFrame());
frames.push(_get256ColorFrame());
return defaultCodec.encodeGif(frames, options)
.then(encodedGif => {
options.colorScope = Gif.GlobalColorsOnly;
return defaultCodec.encodeGif(frames, options);
})
.then(encodedGif => {
assert(true);
})
});
it("uses a global color table when 255 colors + transparency in each of 2 frames", () => {
const frames = [];
const options = { colorScope: Gif.GlobalColorsPreferred };
frames.push(_get256ColorFrame());
frames[0].bitmap.data[3] = 0;
frames.push(_get256ColorFrame());
frames[1].bitmap.data[3] = 0;
return defaultCodec.encodeGif(frames, options)
.then(encodedGif => {
options.colorScope = Gif.GlobalColorsOnly;
return defaultCodec.encodeGif(frames, options);
})
.then(encodedGif => {
assert(true);
})
});
it("uses a local color table when there are 257 opaque colors", () => {
const frames = [];
const options = { colorScope: Gif.GlobalColorsPreferred };
frames.push(_get256ColorFrame());
// put a 257th opaque color in the second frame
let buf = new Buffer(256 * 4); // defaults to zeroes
buf[0] = 0; buf[1] = 2; buf[2] = 3; buf[3] = 255;
frames.push(new GifFrame(16, 16, buf));
return defaultCodec.encodeGif(frames, options)
.then(encodedGif => {
options.colorScope = Gif.GlobalColorsOnly;
return defaultCodec.encodeGif(frames, options);
})
.then(encodedGif => {
assert.fail("should not encode");
})
.catch(err => {
if (!(err instanceof GifError)) {
throw err;
}
assert.strictEqual(err.message,
"Too many color indexes for global color table");
});
});
it("uses a local color table when there are 256 opaque colors + transparency", () => {
const frames = [];
const options = { colorScope: Gif.GlobalColorsPreferred };
frames.push(_get256ColorFrame());
frames.push(_get256ColorFrame());
frames[1].bitmap.data[3] = 0;
return defaultCodec.encodeGif(frames, options)
.then(encodedGif => {
options.colorScope = Gif.GlobalColorsOnly;
return defaultCodec.encodeGif(frames, options);
})
.then(encodedGif => {
assert.fail("should not encode");
})
.catch(err => {
if (!(err instanceof GifError)) {
throw err;
}
assert.strictEqual(err.message,
"Too many color indexes for global color table");
});
});
});
function _compareGifs(actual, expected, filename, note) {
note = `file '${filename}' (${note})`;
assert.strictEqual(actual.width, expected.width, note);
assert.strictEqual(actual.height, expected.height, note);
assert.strictEqual(actual.loops, expected.loops, note);
assert.strictEqual(actual.usesTransparency, expected.usesTransparency,
note);
assert(Buffer.isBuffer(actual.buffer), note);
assert(Array.isArray(actual.frames));
assert.strictEqual(actual.frames.length, expected.frames.length);
note = ` in ${note}`;
for (let i = 0; i < actual.frames.length; ++i) {
const actualFrame = actual.frames[i];
const expectedFrame = expected.frames[i];
Tools.verifyFrameInfo(actualFrame, expectedFrame, i, note);
}
}
function _encodeDecodeFile(filename, colorScope, codec) {
let expectedGif;
codec = codec || defaultCodec;
return GifUtil.read(Tools.getGifPath(filename), codec)
.then(readGif => {
expectedGif = readGif;
return codec.encodeGif(readGif.frames,
{ loops: readGif.loops, colorScope: colorScope });
})
.then(encodedGif => {
_compareGifs(encodedGif, expectedGif, filename,
`encoded == read (colorScope ${colorScope})`);
return codec.decodeGif(encodedGif.buffer);
})
.then(decodedGif => {
_compareGifs(decodedGif, expectedGif, filename,
`decoded == read (colorScope ${colorScope})`);
})
}
function _get256ColorFrame() {
let buf = new Buffer(256 * 4);
for (let i = 0; i < 256; ++i) {
const offset = i * 4;
buf[offset + 2] = buf[offset + 1] = buf[offset] = i;
buf[offset + 3] = 255;
}
return new GifFrame(16, 16, buf);
}