eric/as-dithered-image
1
0
Fork 0
mirror of https://github.com/andrewstephens75/as-dithered-image.git synced 2026-04-14 12:29:30 -07:00
Code Issues Packages Projects Releases Wiki Activity

Added cutoff

Browse Source
This commit is contained in:
Andrew Stephens
2023-01-02 16:59:16 -05:00
parent 7cd9f9ac0e
commit a581dbe19c
3 changed files with 49 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
ditherworker.js
View File

@@ -1,13 +1,15 @@
onmessage = function (e) {
console.log("Worker: start", e.data.imageData)
console.log("Worker: start", e.data)
const result = dither(e.data.imageData, e.data.pixelSize)
const result = dither(e.data.imageData, e.data.pixelSize, e.data.cutoff)
const reply = {}
reply.imageData = result
reply.pixelSize = e.data.pixelSize
reply.cutoff = e.data.cutoff
postMessage(reply)
}
function dither(imageData, scaleFactor) {
function dither(imageData, scaleFactor, cutoff) {
let output = new ImageData(imageData.width * scaleFactor, imageData.height * scaleFactor)
for (let i = 0; i < imageData.data.length; i += 4) {
imageData.data[i] = imageData.data[i + 1] = imageData.data[i + 2] = Math.floor(imageData.data[i] * 0.3 + imageData.data[i + 1] * 0.59 + imageData.data[i + 2] * 0.11)
@@ -25,7 +27,7 @@ function dither(imageData, scaleFactor) {
let accumulatedError = Math.floor(slidingErrorWindow[0][x])
let expectedMono = imageData.data[i] + accumulatedError
let monoValue = expectedMono
if (monoValue <= 127) {
if (monoValue <= Math.floor(cutoff * 255)) {
monoValue = 0
} else {
monoValue = 255