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enhancement: add custom max pixel length functionality #43

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enhancement: add custom max pixel length functionality #43

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12 changes: 6 additions & 6 deletions js/thumbhash.js
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,7 @@ export function rgbaToThumbHash(w, h, rgba) {
* @param hash The bytes of the ThumbHash.
* @returns The width, height, and pixels of the rendered placeholder image.
*/
export function thumbHashToRGBA(hash) {
export function thumbHashToRGBA(hash, maxPixel) {
let { PI, min, max, cos, round } = Math

// Read the constants
Expand Down Expand Up @@ -135,8 +135,8 @@ export function thumbHashToRGBA(hash) {

// Decode using the DCT into RGB
let ratio = thumbHashToApproximateAspectRatio(hash)
let w = round(ratio > 1 ? 32 : 32 * ratio)
let h = round(ratio > 1 ? 32 / ratio : 32)
let w = round(ratio > 1 ? maxPixel : maxPixel * ratio)
let h = round(ratio > 1 ? maxPixel / ratio : maxPixel)
let rgba = new Uint8Array(w * h * 4), fx = [], fy = []
for (let y = 0, i = 0; y < h; y++) {
for (let x = 0; x < w; x++, i += 4) {
Expand Down Expand Up @@ -282,7 +282,7 @@ export function rgbaToDataURL(w, h, rgba) {
* @param hash The bytes of the ThumbHash.
* @returns A data URL containing a PNG for the rendered ThumbHash.
*/
export function thumbHashToDataURL(hash) {
let image = thumbHashToRGBA(hash)
export function thumbHashToDataURL(hash, maxPixel = 32) {
let image = thumbHashToRGBA(hash, maxPixel)
return rgbaToDataURL(image.w, image.h, image.rgba)
}
}