Closed nopparideko closed 6 years ago
I have problem when i use png image. But i found code to fix this problem. please change code to `PNG.prototype.decodePixels = function(fn) { var _this = this; return zlib.inflate(this.imgData, function(err, data) { if (err) throw err; var pixelBytes = _this.pixelBitlength / 8; var fullPixels = new Buffer(_this.width _this.height pixelBytes); var pos = 0; function pass(x0, y0, dx, dy) { var byte, c, col, i, left, p, pa, paeth, pb, pc, pixels, row, scanlineLength, upper, upperLeft; var w = Math.ceil((_this.width - x0) / dx), h = Math.ceil((_this.height - y0) / dy); var isFull = _this.width == w && _this.height == h; scanlineLength = pixelBytes w; pixels = isFull ? fullPixels : new Buffer(scanlineLength h); row = 0; c = 0; while (row < h && pos < data.length) { switch (data[pos++]) { case 0: for (i = 0; i < scanlineLength; i += 1) { pixels[c++] = data[pos++]; } break; case 1: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; pixels[c++] = (byte + left) % 256; } break; case 2: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; upper = row && pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; pixels[c++] = (upper + byte) % 256; } break; case 3: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; upper = row && pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; pixels[c++] = (byte + Math.floor((left + upper) / 2)) % 256; } break; case 4: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; if (row === 0) { upper = upperLeft = 0; } else { upper = pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; upperLeft = col && pixels[(row - 1) scanlineLength + (col - 1) pixelBytes + (i % pixelBytes)]; } p = left + upper - upperLeft; pa = Math.abs(p - left); pb = Math.abs(p - upper); pc = Math.abs(p - upperLeft); if (pa <= pb && pa <= pc) { paeth = left; } else if (pb <= pc) { paeth = upper; } else { paeth = upperLeft; } pixels[c++] = (byte + paeth) % 256; } break; default: throw new Error("Invalid filter algorithm: " + data[pos - 1]); } if (!isFull) { var fullPos = ((y0 + row dy) _this.width + x0) pixelBytes; var partPos = row scanlineLength; for (i = 0; i < w; i += 1) { for (var j = 0; j < pixelBytes; j += 1) fullPixels[fullPos++] = pixels[partPos++]; fullPos += (dx - 1) pixelBytes; } } row++; } } if (_this.interlaceMethod == 1) { / 1 6 4 6 2 6 4 6 7 7 7 7 7 7 7 7 5 6 5 6 5 6 5 6 7 7 7 7 7 7 7 7 3 6 4 6 3 6 4 6 7 7 7 7 7 7 7 7 5 6 5 6 5 6 5 6 7 7 7 7 7 7 7 7 / pass(0, 0, 8, 8); // 1 / NOTE these seem to follow the pattern:
on file png-node.js #8
I have problem when i use png image. But i found code to fix this problem. please change code to `PNG.prototype.decodePixels = function(fn) { var _this = this; return zlib.inflate(this.imgData, function(err, data) { if (err) throw err; var pixelBytes = _this.pixelBitlength / 8; var fullPixels = new Buffer(_this.width _this.height pixelBytes); var pos = 0; function pass(x0, y0, dx, dy) { var byte, c, col, i, left, p, pa, paeth, pb, pc, pixels, row, scanlineLength, upper, upperLeft; var w = Math.ceil((_this.width - x0) / dx), h = Math.ceil((_this.height - y0) / dy); var isFull = _this.width == w && _this.height == h; scanlineLength = pixelBytes w; pixels = isFull ? fullPixels : new Buffer(scanlineLength h); row = 0; c = 0; while (row < h && pos < data.length) { switch (data[pos++]) { case 0: for (i = 0; i < scanlineLength; i += 1) { pixels[c++] = data[pos++]; } break; case 1: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; pixels[c++] = (byte + left) % 256; } break; case 2: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; upper = row && pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; pixels[c++] = (upper + byte) % 256; } break; case 3: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; upper = row && pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; pixels[c++] = (byte + Math.floor((left + upper) / 2)) % 256; } break; case 4: for (i = 0; i < scanlineLength; i += 1) { byte = data[pos++]; col = (i - (i % pixelBytes)) / pixelBytes; left = i < pixelBytes ? 0 : pixels[c - pixelBytes]; if (row === 0) { upper = upperLeft = 0; } else { upper = pixels[(row - 1) scanlineLength + col pixelBytes + (i % pixelBytes)]; upperLeft = col && pixels[(row - 1) scanlineLength + (col - 1) pixelBytes + (i % pixelBytes)]; } p = left + upper - upperLeft; pa = Math.abs(p - left); pb = Math.abs(p - upper); pc = Math.abs(p - upperLeft); if (pa <= pb && pa <= pc) { paeth = left; } else if (pb <= pc) { paeth = upper; } else { paeth = upperLeft; } pixels[c++] = (byte + paeth) % 256; } break; default: throw new Error("Invalid filter algorithm: " + data[pos - 1]); } if (!isFull) { var fullPos = ((y0 + row dy) _this.width + x0) pixelBytes; var partPos = row scanlineLength; for (i = 0; i < w; i += 1) { for (var j = 0; j < pixelBytes; j += 1) fullPixels[fullPos++] = pixels[partPos++]; fullPos += (dx - 1) pixelBytes; } } row++; } } if (_this.interlaceMethod == 1) { / 1 6 4 6 2 6 4 6 7 7 7 7 7 7 7 7 5 6 5 6 5 6 5 6 7 7 7 7 7 7 7 7 3 6 4 6 3 6 4 6 7 7 7 7 7 7 7 7 5 6 5 6 5 6 5 6 7 7 7 7 7 7 7 7 / pass(0, 0, 8, 8); // 1 / NOTE these seem to follow the pattern:
on file png-node.js #8