diff options
Diffstat (limited to 'adapter')
| -rw-r--r-- | adapter/img/sixel.nim | 71 |
1 files changed, 38 insertions, 33 deletions
diff --git a/adapter/img/sixel.nim b/adapter/img/sixel.nim index 19c3782d..f813ae77 100644 --- a/adapter/img/sixel.nim +++ b/adapter/img/sixel.nim @@ -42,7 +42,7 @@ proc die(s: string) {.noreturn.} = os.puts(s) quit(1) -const DCSSTART = "\eP" +const DCS = "\eP" const ST = "\e\\" proc setU32BE(s: var string; n: uint32; at: int) = @@ -157,16 +157,8 @@ proc trim(trimMap: var TrimMap; K: var uint) = ) K = k -proc getPixel(img: openArray[RGBAColorBE]; m: int; bgcolor: ARGBColor): RGBColor - {.inline.} = - let c0 = img[m].toARGBColor() - if c0.a != 255: - let c1 = bgcolor.blend(c0) - return RGBColor(uint32(c1).fastmul(100)) - return RGBColor(uint32(c0).fastmul(100)) - -proc quantize(img: openArray[RGBAColorBE]; bgcolor: ARGBColor; outk: var uint): - NodeChildren = +proc quantize(img: openArray[RGBAColorBE]; outk: var uint; + outTransparent: var bool): NodeChildren = var root = default(NodeChildren) if outk <= 2: # monochrome; not much we can do with an octree... root[0] = cast[Node](alloc0(sizeof(NodeObj))) @@ -181,12 +173,16 @@ proc quantize(img: openArray[RGBAColorBE]; bgcolor: ARGBColor; outk: var uint): # map of non-leaves for each level. # (note: somewhat confusingly, this actually starts at level 1.) var trimMap: array[7, seq[Node]] - for i in 0 ..< img.len: - let c = img.getPixel(i, bgcolor) + var transparent = false + for c0 in img: + let c0 = c0.toARGBColor() + transparent = transparent or c0.a != 255 + let c = RGBColor(uint32(c0).fastmul(100)) K += root.insert(c, trimMap) while K > palette: trimMap.trim(K) outk = K + outTransparent = transparent return root proc flatten(children: NodeChildren; cols: var seq[Node]) = @@ -211,18 +207,19 @@ proc flatten(root: NodeChildren; outs: var string; palette: uint): seq[Node] = return cols type - DitherDiff = tuple[r, g, b: int32] + DitherDiff = tuple[a, r, g, b: int32] Dither = object d1: seq[DitherDiff] d2: seq[DitherDiff] -proc getColor(nodes: seq[Node]; c: RGBColor; diff: var DitherDiff): Node = +proc getColor(nodes: seq[Node]; c: ARGBColor; diff: var DitherDiff): Node = var child: Node = nil var minDist = uint32.high var mdiff = default(DitherDiff) for node in nodes: let ic = node.u.leaf.c + let ad = int32(c.a) - 100 let rd = int32(c.r) - int32(ic.r) let gd = int32(c.g) - int32(ic.g) let bd = int32(c.b) - int32(ic.b) @@ -230,13 +227,13 @@ proc getColor(nodes: seq[Node]; c: RGBColor; diff: var DitherDiff): Node = if d < minDist: minDist = d child = node - mdiff = (rd, gd, bd) + mdiff = (ad, rd, gd, bd) if ic == c: break diff = mdiff return child -proc getColor(root: var NodeChildren; c: RGBColor; nodes: seq[Node]; +proc getColor(root: var NodeChildren; c: ARGBColor; nodes: seq[Node]; diff: var DitherDiff): int = if nodes.len < 64: # Octree-based nearest neighbor search creates really ugly artifacts @@ -259,7 +256,7 @@ proc getColor(root: var NodeChildren; c: RGBColor; nodes: seq[Node]; var level = 0 var children = addr root while true: - let idx = c.getIdx(level) + let idx = RGBColor(c).getIdx(level) let child = children[idx] if child == nil: let child = nodes.getColor(c, diff) @@ -267,31 +264,34 @@ proc getColor(root: var NodeChildren; c: RGBColor; nodes: seq[Node]; return child.idx if child.idx != -1: let ic = child.u.leaf.c + let a = int32(c.a) - 100 let r = int32(c.r) - int32(ic.r) let g = int32(c.g) - int32(ic.g) let b = int32(c.b) - int32(ic.b) - diff = (r, g, b) + diff = (a, r, g, b) return child.idx inc level children = addr child.u.children -proc correctDither(c: RGBColor; x: int; dither: Dither): RGBColor = - let (rd, gd, bd) = dither.d1[x + 1] +proc correctDither(c: ARGBColor; x: int; dither: Dither): ARGBColor = + let (ad, rd, gd, bd) = dither.d1[x + 1] + let pa = (uint32(c) shr 20) and 0xFF0 let pr = (uint32(c) shr 12) and 0xFF0 let pg = (uint32(c) shr 4) and 0xFF0 let pb = (uint32(c) shl 4) and 0xFF0 {.push overflowChecks: off.} + let a = uint8(uint32(clamp(int32(pa) + ad, 0, 1600)) shr 4) let r = uint8(uint32(clamp(int32(pr) + rd, 0, 1600)) shr 4) let g = uint8(uint32(clamp(int32(pg) + gd, 0, 1600)) shr 4) let b = uint8(uint32(clamp(int32(pb) + bd, 0, 1600)) shr 4) {.pop.} - return rgb(r, g, b) + return rgba(r, g, b, a) proc fs(dither: var Dither; x: int; d: DitherDiff) = let x = x + 1 # skip first bounds check template at(p, mul: untyped) = - var (rd, gd, bd) = p - p = (rd + d.r * mul, gd + d.g * mul, bd + d.b * mul) + var (ad, rd, gd, bd) = p + p = (ad + d.a * mul, rd + d.r * mul, gd + d.g * mul, bd + d.b * mul) {.push overflowChecks: off.} at(dither.d1[x + 1], 7) at(dither.d2[x - 1], 3) @@ -367,16 +367,18 @@ proc createBands(bands: var seq[SixelBand]; activeChunks: seq[ptr SixelChunk]) = bands.add(SixelBand(head: chunk, tail: chunk)) proc encode(img: openArray[RGBAColorBE]; width, height, offx, offy, cropw: int; - halfdump: bool; bgcolor: ARGBColor; palette: int) = + halfdump: bool; palette: int) = var palette = uint(palette) - var root = img.quantize(bgcolor, palette) + var transparent = false + var root = img.quantize(palette, transparent) # prelude var outs = "Cha-Image-Dimensions: " & $width & 'x' & $height & "\n\n" let preludeLenPos = outs.len if halfdump: # reserve size for prelude outs &= "\0\0\0\0" + outs &= char(transparent) else: - outs &= DCSSTART & 'q' + outs &= DCS & 'q' # set raster attributes outs &= "\"1;1;" & $width & ';' & $height let nodes = root.flatten(outs, palette) @@ -410,9 +412,15 @@ proc encode(img: openArray[RGBAColorBE]; width, height, offx, offy, cropw: int; var chunk: ptr SixelChunk = nil for j in 0 ..< realw: let m = n + offx + j - let c0 = img.getPixel(m, bgcolor).correctDither(j, dither) + let c0 = img[m].toARGBColor() + let c1 = ARGBColor(uint32(c0).fastmul1(100)) + let c2 = c1.correctDither(j, dither) + if c2.a < 50: # transparent + let diff = (int32(c2.a), 0i32, 0i32, 0i32) + dither.fs(j, diff) + continue var diff: DitherDiff - let c = root.getColor(c0, nodes, diff) + let c = root.getColor(c2, nodes, diff) dither.fs(j, diff) if chunk == nil or chunk.c != c: chunk = addr chunkMap[c] @@ -492,7 +500,6 @@ proc main() = var offy = 0 var halfdump = false var palette = -1 - var bgcolor = rgb(0, 0, 0) var cropw = -1 var quality = -1 for hdr in getEnv("REQUEST_HEADERS").split('\n'): @@ -519,8 +526,6 @@ proc main() = if q.isNone: die("Cha-Control: ConnectionError 1 wrong quality\n") quality = int(q.get) - of "Cha-Image-Background-Color": - bgcolor = parseLegacyColor0(s) if cropw == -1: cropw = width if palette == -1: @@ -543,7 +548,7 @@ proc main() = enterNetworkSandbox() # don't swallow stat let p = cast[ptr UncheckedArray[RGBAColorBE]](src.p) p.toOpenArray(0, n - 1).encode(width, height, offx, offy, cropw, halfdump, - bgcolor, palette) + palette) dealloc(src) main() |