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| "use strict";
|
| // Adam 7
| // 0 1 2 3 4 5 6 7
| // 0 x 6 4 6 x 6 4 6
| // 1 7 7 7 7 7 7 7 7
| // 2 5 6 5 6 5 6 5 6
| // 3 7 7 7 7 7 7 7 7
| // 4 3 6 4 6 3 6 4 6
| // 5 7 7 7 7 7 7 7 7
| // 6 5 6 5 6 5 6 5 6
| // 7 7 7 7 7 7 7 7 7
|
| let imagePasses = [
| {
| // pass 1 - 1px
| x: [0],
| y: [0],
| },
| {
| // pass 2 - 1px
| x: [4],
| y: [0],
| },
| {
| // pass 3 - 2px
| x: [0, 4],
| y: [4],
| },
| {
| // pass 4 - 4px
| x: [2, 6],
| y: [0, 4],
| },
| {
| // pass 5 - 8px
| x: [0, 2, 4, 6],
| y: [2, 6],
| },
| {
| // pass 6 - 16px
| x: [1, 3, 5, 7],
| y: [0, 2, 4, 6],
| },
| {
| // pass 7 - 32px
| x: [0, 1, 2, 3, 4, 5, 6, 7],
| y: [1, 3, 5, 7],
| },
| ];
|
| exports.getImagePasses = function (width, height) {
| let images = [];
| let xLeftOver = width % 8;
| let yLeftOver = height % 8;
| let xRepeats = (width - xLeftOver) / 8;
| let yRepeats = (height - yLeftOver) / 8;
| for (let i = 0; i < imagePasses.length; i++) {
| let pass = imagePasses[i];
| let passWidth = xRepeats * pass.x.length;
| let passHeight = yRepeats * pass.y.length;
| for (let j = 0; j < pass.x.length; j++) {
| if (pass.x[j] < xLeftOver) {
| passWidth++;
| } else {
| break;
| }
| }
| for (let j = 0; j < pass.y.length; j++) {
| if (pass.y[j] < yLeftOver) {
| passHeight++;
| } else {
| break;
| }
| }
| if (passWidth > 0 && passHeight > 0) {
| images.push({ width: passWidth, height: passHeight, index: i });
| }
| }
| return images;
| };
|
| exports.getInterlaceIterator = function (width) {
| return function (x, y, pass) {
| let outerXLeftOver = x % imagePasses[pass].x.length;
| let outerX =
| ((x - outerXLeftOver) / imagePasses[pass].x.length) * 8 +
| imagePasses[pass].x[outerXLeftOver];
| let outerYLeftOver = y % imagePasses[pass].y.length;
| let outerY =
| ((y - outerYLeftOver) / imagePasses[pass].y.length) * 8 +
| imagePasses[pass].y[outerYLeftOver];
| return outerX * 4 + outerY * width * 4;
| };
| };
|
|
