bv7_canvas

canvas

Αυτός ο κώδικας δεν πρέπει να εγκατασταθεί άμεσα. Είναι μια βιβλιοθήκη για άλλους κώδικες που περιλαμβάνεται μέσω της οδηγίας meta // @require https://update.greatest.deepsurf.us/scripts/39480/258533/bv7_canvas.js

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey, το Greasemonkey ή το Violentmonkey για να εγκαταστήσετε αυτόν τον κώδικα.

You will need to install an extension such as Tampermonkey to install this script.

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey ή το Violentmonkey για να εγκαταστήσετε αυτόν τον κώδικα.

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey ή το Userscripts για να εγκαταστήσετε αυτόν τον κώδικα.

You will need to install an extension such as Tampermonkey to install this script.

Θα χρειαστεί να εγκαταστήσετε μια επέκταση διαχείρισης κώδικα χρήστη για να εγκαταστήσετε αυτόν τον κώδικα.

(Έχω ήδη έναν διαχειριστή κώδικα χρήστη, επιτρέψτε μου να τον εγκαταστήσω!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Έχω ήδη έναν διαχειριστή στυλ χρήστη, επιτρέψτε μου να τον εγκαταστήσω!)

// ==UserScript==
// @name         bv7_canvas
// @namespace    bv7
// @version      0.3
// @description  canvas
// @author       bv7
// @require      https://greatest.deepsurf.us/scripts/39476-bv7-jpeg-encoder/code/bv7_jpeg_encoder.js
// @require      https://greatest.deepsurf.us/scripts/39479-bv7-jpeg2array/code/bv7_jpeg2array.js
// ==/UserScript==

class Canvas {
	constructor() {
		this.domCanvas = document.createElement('canvas');
		this.jpegEncoder = new JpegEncoder();
	}
	set width(v) {
		this.domCanvas.width = v;
		this.onresize();
	}
	set height(v) {
		this.domCanvas.height = v;
		this.onresize();
	}
	get width () {
		return this.domCanvas.width;
	}
	get height() {
		return this.domCanvas.height;
	}
	onresize() {
	}
	getContext(_id) {
		switch (_id) {
			case '2d':
				this.context = new class {
					constructor(canvas) {
						this.canvas     = canvas;
						this.domContext = this.canvas.domCanvas.getContext('2d');
						this.imageData  = this.domContext.getImageData(0, 0, this.canvas.domCanvas.width, this.canvas.domCanvas.height);
					}
					drawImage(image, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight, then) {
						let myImage;
						let draw = () => {
							if (dWidth && sWidth && dHeight && sHeight) {
								let syStep  = sHeight / dHeight;
								let sxStep  = sWidth  / dWidth;
								let dyStep  = dHeight / sHeight;
								let dxStep  = dWidth  / sWidth ;
								let syStart = Math.max(0, sy, sy - dy / dyStep);
								let sxStart = Math.max(0, sx, sx - dx / dxStep);
								let syEnd   = Math.min(myImage.height, sy + sHeight, sy + (this.imageData.height - dy) / dyStep);
								let sxEnd   = Math.min(myImage.width , sx + sWidth , sx + (this.imageData.width  - dx) / dxStep);
								let dyStart = dy + (syStart - sy) * dyStep;
								let dxStart = dx + (sxStart - sx) * dxStep;
								let dyEnd   = dy + (syEnd   - sy) * dyStep;
								let dxEnd   = dx + (sxEnd   - sx) * dxStep;
								let sh1 = Math.max(1, syStep);
								let sw1 = Math.max(1, sxStep);
								let dh1 = Math.max(1, dyStep);
								let dw1 = Math.max(1, dxStep);
								let siPerLine, siStartLine, siStart;
								let diPerLine, diStartLine, diStart;
								let sy1, sy1Next, sy2Start, sy2End;
								let sx1, sx1Next, sx2Start, sx2End;
								let dy1, dy1Next, dy2Start, dy2End;
								let dx1, dx1Next, dx2Start, dx2End;
								let s2count;
								let r, g, b, a;
								siPerLine = myImage.imageData.width * 4;
								diPerLine =    this.imageData.width * 4;
								sy2Start  = Math.round(sy1 = syStart);
								dy2Start  = Math.round(dy1 = dyStart);
								while (sy1 < syEnd) {
									sy2End   = Math.round(sy1Next = sy1 + sh1);
									dy2End   = Math.round(dy1Next = dy1 + dh1);
									sx2Start = Math.round(sx1 = sxStart);
									dx2Start = Math.round(dx1 = dxStart);
									siStartLine = sy2Start * siPerLine;
									diStartLine = dy2Start * diPerLine;
									while (sx1 < sxEnd) {
										sx2End  = Math.round(sx1Next = sx1 + sw1);
										dx2End  = Math.round(dx1Next = dx1 + dw1);
										siStart = siStartLine + sx2Start * 4;
										diStart = diStartLine + dx2Start * 4;
										s2count = (sy2End - sy2Start) * (sx2End - sx2Start);
										r = g = b = a = 0;
										for (let sy2 = sy2Start; sy2 < sy2End; sy2++, siStart += siPerLine) for (let sx2 = sx2Start, si = siStart; sx2 < sx2End; sx2++) {
											r += myImage.imageData.data[si++];
											g += myImage.imageData.data[si++];
											b += myImage.imageData.data[si++];
											a += myImage.imageData.data[si++];
										}
										for (let dy2 = dy2Start; dy2 < dy2End; dy2++, diStart += diPerLine) for (let dx2 = dx2Start, di = diStart; dx2 < dx2End; dx2++) {
											this.imageData.data[di++] = (r - r % s2count) / s2count;
											this.imageData.data[di++] = (g - g % s2count) / s2count;
											this.imageData.data[di++] = (b - b % s2count) / s2count;
											this.imageData.data[di++] = (a - a % s2count) / s2count;
										}
										sx1      = sx1Next;
										dx1      = dx1Next;
										sx2Start = sx2End;
										dx2Start = dx2End;
									}
									sy1      = sy1Next;
									dy1      = dy1Next;
									sy2Start = sy2End;
									dy2Start = dy2End;
								}
								this.domContext.putImageData(this.imageData, 0, 0);
							}
							if (then) then();
						};
						if (Canvas.images.some((v) => (myImage = v).src == image.src)) 
							draw();
						else {
							myImage = new JpegImage();
							myImage.onload = () => {
								myImage.imageData = this.domContext.createImageData(myImage.width, myImage.height);
								myImage.copyToImageData(myImage.imageData);
								Canvas.images.push(myImage);
								draw();
							};
							myImage.src = image.src;
						}
					};
				} (this);
				break;
		}
		return this.context;
	}
	toDataUrl(type = 'image/png', encoderOptions = 0.92) {
		let r;
		switch (type) {
			case 'image/jpeg':
				r = this.jpegEncoder.encode(this.context.imageData, encoderOptions);
				break;
			default:
				r = '';
		}
		return r;
	}
}
Canvas.images = [];