mirror of
https://github.com/Investigamer/cardconjurer.git
synced 2025-07-27 13:21:41 -05:00
57 lines
2.6 KiB
JavaScript
57 lines
2.6 KiB
JavaScript
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var transparentCanvas = document.createElement("canvas")
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var transparentContext = transparentCanvas.getContext("2d")
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//transparentCanvas.onload = function() {
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//document.body.appendChild(transparentCanvas) //For testing purposes only
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//}
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transparentCanvas.onload = function() {
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alert("WHAT")
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}
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//document.body.appendChild(transparentCanvas)
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//Function that auto the image
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function whiteToTransparent(url, destination) {
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//Create image, size canvas, draw image
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var imgTempSetSymbol = new Image()
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imgTempSetSymbol.crossOrigin = "anonymous"
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imgTempSetSymbol.src = url
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imgTempSetSymbol.onload = function() {
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if (imgTempSetSymbol.width > 0 && imgTempSetSymbol.height > 0) {
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transparentCanvas.width = imgTempSetSymbol.width
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transparentCanvas.height = imgTempSetSymbol.height
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transparentCanvas.drawImage(imgTempSetSymbol, 0, 0)
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//declare variables
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var width = transparentCanvas.width
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var height = transparentCanvas.height
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var pix = {x:[], y:[]}
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var imageData = transparentContext.getImageData(0,0,transparentCanvas.width,transparentCanvas.height)
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var x, y, index
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//Go through every pixel and
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for (y = 0; y < height; y++) {
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for (x = 0; x < width; x++) {
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//(y * width + x) * 4 + 3 calculates the index at which the alpha value of the pixel at x, y is given
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index = (y * width + x) * 4 + 3
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if (imageData.data[index] > 0) {
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//pix is the image object that stores two arrays of x and y coordinates. These stored coordinates are all the visible pixels
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pix.x.push(x)
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pix.y.push(y)
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}
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}
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}
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//sorts the arrays numerically
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pix.x.sort(function(a,b){return a-b})
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pix.y.sort(function(a,b){return a-b})
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var n = pix.x.length - 1
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//Finds the difference between the leftmost and rightmost visible pixels, and the topmost and bottommost pixels, cuts out a section of the canvas
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width = pix.x[n] - pix.x[0]
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height = pix.y[n] - pix.y[0]
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var transparentImage = transparentContext.getImageData(pix.x[0], pix.y[0], width + 1, height + 1)
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//Resizes the canvas and draws image
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transparentCanvas.width = width + 1
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transparentCanvas.height = height + 1
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transparentContext.putImageData(transparentImage, 0, 0)
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//Saves the newly image to the given image
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destination.src = transparentCanvas.toDataURL()
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}
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}
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}
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