| 57 | // get palette() |
| 58 | |
| 59 | static decompress(data, pixelFormat, alpha) { |
| 60 | let png = new PNG(data); |
| 61 | let width = png.width, height = png.height, channels = png.channels, depth = png.depth, palette = png.palette ? new Uint8Array(png.palette) : undefined; |
| 62 | |
| 63 | if ((8 == depth) && (((3 == channels) || (4 == channels)) || ((1 == channels) && palette))) { // RGB (24) or RGBA (32) or indexed (8) |
| 64 | let image = new BufferOut({width, height, pixelFormat}); |
| 65 | image.begin(0, 0, width, height); |
| 66 | let scanOut = new ArrayBuffer((width * Bitmap.depth(pixelFormat)) >> 3); |
| 67 | let convert = new Converter((3 == channels) ? Bitmap.RGB24 : Bitmap.RGBA32, pixelFormat); |
| 68 | |
| 69 | let mask, scanAlpha; |
| 70 | if (alpha && ((4 == channels) || palette)) { |
| 71 | mask = new BufferOut({width: width, height: height, pixelFormat: alpha}); // only works when alpha is Bitmap.Gray16 |
| 72 | mask.begin(0, 0, width, height); |
| 73 | scanAlpha = new Uint8Array(scanOut); |
| 74 | } |
| 75 | |
| 76 | for (let i = 0; i < height; i++) { |
| 77 | let scanLine = png.read(); |
| 78 | |
| 79 | if (palette) { |
| 80 | //@@ need a converter! |
| 81 | for (let j = 0; j < width; j++) { |
| 82 | let offset = scanLine[j] * 4; |
| 83 | let r = palette[offset ]; |
| 84 | let g = palette[offset + 1]; |
| 85 | let b = palette[offset + 2]; |
| 86 | scanOut[j] = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3); |
| 87 | } |
| 88 | } |
| 89 | else |
| 90 | convert.process(scanLine.buffer, scanOut); |
| 91 | image.send(scanOut); |
| 92 | |
| 93 | if (mask) { |
| 94 | //@ converters! |
| 95 | if (palette) { |
| 96 | for (let j = 0; j < width; j += 2) { |
| 97 | let a0 = palette[(scanLine[j] * 4) + 3]; |
| 98 | let a1 = palette[(scanLine[j + 1] * 4) + 3]; |
| 99 | scanAlpha[j >> 1] = ~((a0 & 0xf0) | (a1 >> 4)); |
| 100 | } |
| 101 | } |
| 102 | else { |
| 103 | for (let j = 0, offset = 3; j < (width >> 1); j++, offset += (channels << 1)) { |
| 104 | let a0 = scanLine[offset]; |
| 105 | let a1 = scanLine[offset + channels]; |
| 106 | scanAlpha[j] = ~((a0 & 0xf0) | (a1 >> 4)); |
| 107 | } |
| 108 | } |
| 109 | mask.send(scanAlpha.buffer, 0, width >> 1); |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | image.end(); |
| 114 | image = image.bitmap; |
| 115 | if (mask) { |
| 116 | mask.end(); |