diff options
Diffstat (limited to 'adapter')
| -rw-r--r-- | adapter/img/sixel.nim | 152 |
1 files changed, 97 insertions, 55 deletions
diff --git a/adapter/img/sixel.nim b/adapter/img/sixel.nim index e9b4c115..f09166f6 100644 --- a/adapter/img/sixel.nim +++ b/adapter/img/sixel.nim @@ -43,41 +43,6 @@ proc die(s: string) {.noreturn.} = const DCSSTART = "\eP" const ST = "\e\\" -type SixelBand = object - c: int - data: seq[uint8] - -# data is binary 0..63; the output is the final ASCII form. -proc compressSixel(band: SixelBand): string = - var outs = newStringOfCap(band.data.len div 4 + 3) - outs &= '#' - outs &= $band.c - var n = 0 - var c = char(0) - for u in band.data: - let cc = char(u + 0x3F) - if c != cc: - if n > 3: - outs &= '!' & $n & c - else: # for char(0) n is also 0, so it is ignored. - for i in 0 ..< n: - outs &= c - c = cc - n = 0 - inc n - if n > 3: - outs &= '!' & $n & c - else: - for i in 0 ..< n: - outs &= c - return outs - -func find(bands: seq[SixelBand]; c: int): int = - for i in 0 ..< bands.len: - if bands[i].c == c: - return i - return -1 - proc setU32BE(s: var string; n: uint32; at: int) = s[at] = char(n and 0xFF) s[at + 1] = char((n shr 8) and 0xFF) @@ -291,6 +256,67 @@ proc fs(dither: var Dither; x: int; d: DitherDiff) = at(dither.d2[x], 5) at(dither.d2[x + 1], 1) +type + SixelBand = seq[ptr SixelChunk] + + SixelChunk = object + x: int + c: int + nrow: int + data: seq[uint8] + +# data is binary 0..63; the output is the final ASCII form. +proc compressSixel(outs: var string; band: SixelBand) = + var x = 0 + for chunk in band: + outs &= '#' + outs &= $chunk.c + let diff = chunk.x - x + if diff > 3: + outs &= '!' & $diff & '?' + else: + for i in 0 ..< diff: + outs &= '?' + x = chunk.x + chunk.data.len + var n = 0 + var c = char(0) + for u in chunk.data: + let cc = char(u + 0x3F) + if c != cc: + if n > 3: + outs &= '!' & $n & c + else: # for char(0) n is also 0, so it is ignored. + for i in 0 ..< n: + outs &= c + c = cc + n = 0 + inc n + if n > 3: + outs &= '!' & $n & c + else: + for i in 0 ..< n: + outs &= c + +proc createBands(bands: var seq[SixelBand]; chunkMap: seq[SixelChunk]; + nrow: int) = + for chunk in chunkMap: + if chunk.nrow < nrow: + continue + let x = chunk.x + let ex = chunk.x + chunk.data.len + var found = false + for band in bands.mitems: + if band[0].x > ex: + band.insert(unsafeAddr chunk, 0) + found = true + break + elif band[^1].x + band[^1].data.len <= x: + band.add(unsafeAddr chunk) + found = true + break + if not found: + bands.add(@[unsafeAddr chunk]) + proc encode(s: string; width, height, offx, offy, cropw: int; halfdump: bool; bgcolor: ARGBColor; palette: int) = # reserve one entry for transparency @@ -315,50 +341,65 @@ proc encode(s: string; width, height, offx, offy, cropw: int; halfdump: bool; puts(outs) let W = width * 4 let H = W * height + let realw = cropw - offx var n = offy * W var ymap = "" var totalLen = 0 # add +2 so we don't have to bounds check var dither = Dither( - d1: newSeq[DitherDiff](width + 2), - d2: newSeq[DitherDiff](width + 2) + d1: newSeq[DitherDiff](realw + 2), + d2: newSeq[DitherDiff](realw + 2) ) + var chunkMap = newSeq[SixelChunk](palette) + var nrow = 1 while true: if halfdump: ymap.putU32BE(uint32(totalLen)) - var bands = newSeq[SixelBand]() for i in 0 ..< 6: if n >= H: break let mask = 1u8 shl i - let realw = cropw - offx + var chunk: ptr SixelChunk = nil for j in 0 ..< realw: let x = offx + j let m = n + x * 4 - let c0 = s.getPixel(m, bgcolor).correctDither(x, dither) + let c0 = s.getPixel(m, bgcolor).correctDither(j, dither) var diff: DitherDiff - var c = node.getColor(c0, nodes, diff).idx + let c = node.getColor(c0, nodes, diff).idx dither.fs(x, diff) - #TODO this could be optimized a lot more, by squashing together bands - # with empty runs at different places. - var k = bands.find(c) - if k == -1: - bands.add(SixelBand(c: c, data: newSeq[uint8](realw))) - k = bands.high - bands[k].data[j] = bands[k].data[j] or mask + if chunk == nil or chunk.c != c: + chunk = addr chunkMap[c - 1] + chunk.c = c + if chunk.nrow < nrow: + chunk.nrow = nrow + chunk.x = j + chunk.data.setLen(0) + elif chunk.x > j: + let diff = chunk.x - j + chunk.x = j + let olen = chunk.data.len + chunk.data.setLen(olen + diff) + moveMem(addr chunk.data[diff], addr chunk.data[0], olen) + zeroMem(addr chunk.data[0], diff) + elif chunk.data.len < j - chunk.x: + chunk.data.setLen(j - chunk.x) + let k = j - chunk.x + if k < chunk.data.len: + chunk.data[k] = chunk.data[k] or mask + else: + chunk.data.add(mask) n += W var tmp = move(dither.d1) dither.d1 = move(dither.d2) dither.d2 = move(tmp) zeroMem(addr dither.d2[0], dither.d2.len * sizeof(dither.d2[0])) + var bands: seq[SixelBand] = @[] + bands.createBands(chunkMap, nrow) outs.setLen(0) - var i = 0 - while true: - outs &= bands[i].compressSixel() - inc i - if i >= bands.len: - break - outs &= '$' + for band in bands: + if outs.len > 0: + outs &= '$' + outs.compressSixel(band) if n >= H: outs &= ST totalLen += outs.len @@ -367,6 +408,7 @@ proc encode(s: string; width, height, offx, offy, cropw: int; halfdump: bool; outs &= '-' totalLen += outs.len puts(outs) + inc nrow if halfdump: ymap.putU32BE(uint32(totalLen)) ymap.putU32BE(uint32(ymap.len)) |