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Smoother ALF/ALP

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zefie
2026-04-29 14:45:04 -04:00
parent b294771061
commit d3ffd6c678
3 changed files with 32 additions and 87 deletions
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12
zefie_wtvp_minisrv/app.js
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@@ -1369,22 +1369,20 @@ async function sendToClient(socket, headers_obj, data = null, throttle = 0) {
if (minisrv_config.config.image_decoder && minisrv_config.config.image_decoder.enabled) {
const contype_key = wtvshared.getCaseInsensitiveKey('content-type', headers_obj);
let pngOpts = {};
if (contype_key) {
if (minisrv_config.config.image_decoder.image_formats && minisrv_config.config.image_decoder.image_formats.includes(headers_obj[contype_key].toLowerCase())) {
const convertOpts = {
jpegQuality: minisrv_config.config.image_decoder.jpg_quality,
type: imageArtemisType
type: imageArtemisType,
imgopts: minisrv_config.config.image_decoder.image_options || null
};
if (minisrv_config.config.image_decoder.max_height > 0) convertOpts.maxHeight = minisrv_config.config.image_decoder.max_height;
if (minisrv_config.config.image_decoder.max_width > 0) convertOpts.maxWidth = minisrv_config.config.image_decoder.max_width;
if (minisrv_config.config.image_decoder.png_opts) {
pngOpts = minisrv_config.config.image_decoder.png_opts;
}
const sourceData = Buffer.isBuffer(data) ? data : Buffer.from(data);
try {
const converted = await WTVImage.ImageToWebTV(sourceData, convertOpts, pngOpts);
const converted = await WTVImage.ImageToWebTV(sourceData, convertOpts);
data = converted.data;
content_length = data.length;
var i=0;
@@ -1392,7 +1390,7 @@ async function sendToClient(socket, headers_obj, data = null, throttle = 0) {
// Image is too big, try to reduce quality
if (i < minisrv_config.config.image_decoder.max_quality_tries) {
convertOpts.jpegQuality -= minisrv_config.config.image_decoder.jpeg_interval;
var converted2 = await WTVImage.ImageToWebTV(sourceData, convertOpts);
var converted2 = await WTVImage.ImageToWebTV(sourceData, convertOpts, pngOpts);
data = converted2.data;
content_length = data.length;
i++;

98
zefie_wtvp_minisrv/includes/classes/WTVImage.js
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@@ -540,72 +540,30 @@ class WTVImage {
* It is intentionally dependency-light and avoids requiring native imagequant
* bindings or experimental Node flags.
*/
async quantizeArtemisRGBA(rgbaData, width, height, targetColors) {
async quantizeArtemisRGBA(rgbaData, width, height, opts) {
const pixelCount = width * height;
const quantizeData = Buffer.alloc(pixelCount * 4);
for (let i = 0; i < pixelCount; i++) {
const p = i * 4;
const a = rgbaData[p + 3];
let tier;
if (a === 0) tier = 0;
else if (a >= 224) tier = 7;
else tier = 1 + ((a - 1) >> 5);
quantizeData[p] = ((tier & 0x07) << 5) | (rgbaData[p] >> 3);
quantizeData[p + 1] = rgbaData[p + 1];
quantizeData[p + 2] = rgbaData[p + 2];
quantizeData[p + 3] = 255; // sharp's GIF encoder needs alpha=255 to keep all pixels distinct
}
// Use sharp's PNG palette mode (libimagequant) instead of its GIF
// encoder. GIF only supports 1-bit alpha so its quantizer collapses
// partial-alpha pixels to fully-opaque or fully-transparent before
// clustering, destroying the per-pixel alpha we need to reconstruct.
// libimagequant under the PNG path clusters in true 4D RGBA space
// and gives us per-pixel palette indices we can hand to our own
// alpha-histogram pass.
const pngOpts = {
palette: true,
colors: Math.max(2, Math.min(256, opts.colors || 256)),
// Carry through dither / effort if the caller specified them.
dither: (opts.imgopts && typeof opts.imgopts.dither === 'number') ? opts.imgopts.dither : 1.0,
effort: (opts.imgopts && typeof opts.imgopts.effort === 'number') ? opts.imgopts.effort : 7,
compressionLevel: 0,
};
const quantizedGIFBuf = await sharp(quantizeData, { raw: { width, height, channels: 4 } })
.gif({ colors: targetColors, effort: 10, dither: 0 })
const quantizedPNGBuf = await sharp(rgbaData, { raw: { width, height, channels: 4 } })
.png(pngOpts)
.toBuffer();
const qHdr = this.parseGIFHeader(quantizedGIFBuf);
if (!qHdr.hasGCT) throw new Error('Quantized GIF has no global color table');
const colors = qHdr.gctSize;
let scanPos = 13 + qHdr.gctBytes;
while (scanPos < quantizedGIFBuf.length) {
const b = quantizedGIFBuf[scanPos];
if (b === 0x2C) break;
if (b === 0x3B) throw new Error('No image found in quantized GIF');
if (b === 0x21) {
scanPos += 2;
const label = quantizedGIFBuf[scanPos - 1];
if (label === 0xF9) {
const gceBlockSize = quantizedGIFBuf[scanPos];
scanPos += 1 + gceBlockSize + 1;
} else if (label === 0xFF) {
const appBlockSize = quantizedGIFBuf[scanPos];
scanPos += 1 + appBlockSize;
while (scanPos < quantizedGIFBuf.length && quantizedGIFBuf[scanPos] !== 0) {
scanPos += quantizedGIFBuf[scanPos] + 1;
}
scanPos++;
} else {
while (scanPos < quantizedGIFBuf.length && quantizedGIFBuf[scanPos] !== 0) {
scanPos += quantizedGIFBuf[scanPos] + 1;
}
scanPos++;
}
continue;
}
scanPos++;
}
if (scanPos >= quantizedGIFBuf.length) throw new Error('Could not find image descriptor');
const imgDescStart = scanPos;
const imgDescPacked = quantizedGIFBuf[imgDescStart + 9];
const hasLCT = (imgDescPacked & 0x80) !== 0;
const lctSize = hasLCT ? (1 << ((imgDescPacked & 0x07) + 1)) : 0;
const lzwStart = imgDescStart + 10 + lctSize * 3;
const minCodeSize = quantizedGIFBuf[lzwStart];
const { data: rawLZWData } = this.readSubBlocks(quantizedGIFBuf, lzwStart + 1);
const indices = this.lzwDecode(rawLZWData, minCodeSize, pixelCount);
const { palette: rawPalette, indices, colors } = this.extractPalettePNG(quantizedPNGBuf);
const rSums = new Float64Array(colors);
const gSums = new Float64Array(colors);
@@ -701,12 +659,6 @@ class WTVImage {
const paletteSize = opts.colors || 256;
const type = opts.type || 'ALF';
// Clamp palette size to valid GIF power-of-two values
const validSizes = [2, 4, 8, 16, 32, 64, 128, 256];
const targetColors = validSizes.reduce((prev, cur) =>
Math.abs(cur - paletteSize) < Math.abs(prev - paletteSize) ? cur : prev
);
const sharpSrc = (typeof input === 'string' || Buffer.isBuffer(input))
? sharp(input)
: input;
@@ -718,7 +670,7 @@ class WTVImage {
const { width, height } = info;
const { colors, indices, realPalette, alphaTable, bestZeroIdx } = await this.quantizeArtemisRGBA(rgbaData, width, height, targetColors);
const { colors, indices, realPalette, alphaTable, bestZeroIdx } = await this.quantizeArtemisRGBA(rgbaData, width, height, opts);
const transparentIdx = (type === 'ALF') ? colors - 1 : 0;
const finalIndices = Buffer.from(indices);
@@ -1018,7 +970,7 @@ class WTVImage {
* @param {number} [opts.maxHeight] - maximum height to scale to before encoding
* @returns {Promise<{ data: Buffer, mime: string }>}
*/
async ImageToWebTV(input, opts = {}, pngopts = {}) {
async ImageToWebTV(input, opts = {}) {
let pngBuf = Buffer.isBuffer(input) ? input : require('fs').readFileSync(input);
const maxWidth = Number(opts.maxWidth) > 0 ? Number(opts.maxWidth) : null;
const maxHeight = Number(opts.maxHeight) > 0 ? Number(opts.maxHeight) : null;
@@ -1029,15 +981,9 @@ class WTVImage {
const resizeOpts = { fit: 'inside', withoutEnlargement: true };
if (maxWidth) resizeOpts.width = maxWidth;
if (maxHeight) resizeOpts.height = maxHeight;
const outputPngOpts = Object.assign({}, pngopts);
if (originalIsPalettePNG && outputPngOpts.palette) {
// Avoid an extra palette quantization step on an already-indexed PNG.
outputPngOpts.palette = false;
delete outputPngOpts.colors;
}
pngBuf = await sharp(pngBuf)
.resize(resizeOpts)
.png(outputPngOpts)
.png()
.toBuffer();
}
const meta = willResize ? await sharp(pngBuf).metadata() : inputMeta;

9
zefie_wtvp_minisrv/includes/config.json
View File

@@ -126,10 +126,11 @@
"image/tiff",
"image/webp"
],
"png_opts": {
"quality": 80,
"compressionLevel": 9,
"palette": true,
"image_options": {
"compressionLevel": 0,
"adaptiveFiltering": true,
"dither": 1,
"colors": 256,
"effort": 10
},
"max_height": 2048,