(pixels, offsetIn = 0, count = pixels.byteLength - offsetIn)
| 57 | this.output.firstNybble = true; |
| 58 | } |
| 59 | send(pixels, offsetIn = 0, count = pixels.byteLength - offsetIn) { |
| 60 | let width = this.width; |
| 61 | let halfWidth = (width + 1) >> 1; |
| 62 | |
| 63 | let lines = Math.floor((count * 2) / width); |
| 64 | let scan = this.scan; |
| 65 | const solid = 0; |
| 66 | const skip = 15; |
| 67 | |
| 68 | pixels = new Uint8Array(pixels); |
| 69 | for (let line = 0, offset = offsetIn; line < lines; line++, offset += halfWidth) { |
| 70 | // expand incoming packed 4-bit gray pixels into bytes (if width is odd, expands one extra (unused) pixel) |
| 71 | for (let i = 0, pos = offset; i < width; i += 2, pos += 1) { |
| 72 | scan[i + 0] = pixels[pos] >> 4; |
| 73 | scan[i + 1] = pixels[pos] & 0x0F; |
| 74 | } |
| 75 | |
| 76 | // encode one run |
| 77 | for (let remain = width, pos = 0; remain > 0; ) { |
| 78 | if (remain >= 2) { |
| 79 | // check for skip run |
| 80 | if ((skip === scan[pos]) && (skip === scan[pos + 1])) { |
| 81 | let count = 2; |
| 82 | while (((remain - count) > 0) && (count < 9) && (skip === scan[pos + count])) |
| 83 | count += 1; |
| 84 | this.writeNybble(count - 2); |
| 85 | remain -= count; |
| 86 | pos += count; |
| 87 | continue; |
| 88 | } |
| 89 | |
| 90 | // check for solid run |
| 91 | if ((solid === scan[pos]) && (solid === scan[pos + 1])) { |
| 92 | let count = 2; |
| 93 | while (((remain - count) > 0) && (count < 5) && (solid === scan[pos + count])) |
| 94 | count += 1; |
| 95 | this.writeNybble(0x08 | (count - 2)); |
| 96 | remain -= count; |
| 97 | pos += count; |
| 98 | continue; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | // quote |
| 103 | let quoteLen = 1; |
| 104 | while (quoteLen < 4) { |
| 105 | if (remain < (quoteLen + 2)) { |
| 106 | quoteLen = Math.min(remain, 4); |
| 107 | break; |
| 108 | } |
| 109 | if ((scan[pos + quoteLen] === scan[pos + quoteLen + 1]) && |
| 110 | ((solid === scan[pos + quoteLen]) || (skip === scan[pos + quoteLen]))) |
| 111 | break; |
| 112 | quoteLen += 1; |
| 113 | } |
| 114 | |
| 115 | this.writeNybble(0x0C | (quoteLen - 1)); |
| 116 | for (let i = 0; i < quoteLen; i++) |
no test coverage detected