Adding initial aperture.net version.

aperture.js

@@ -0,0 +1,115 @@
+class Aperture {
+    /**
+     * 
+     * @param {String|HTMLImageElement} image The image to resize, this can be a image element or url, or base64.
+     * @param {Number} newWidth The new width of the image in pixels.
+     * @param {Number} sharpen The sharpen level to apply to the result, from 0 to 1.0. Defaults to 0.5
+     * @returns {Blob} returns the resized image as a new blob.
+     */
+    static async resizeImage(image, newWidth, sharpen = 0.5) {
+        var canvas = document.createElement('canvas');
+        var ctx = canvas.getContext("2d");
+        var oc = document.createElement('canvas');
+        var octx = oc.getContext('2d');
+
+        var img = image;
+
+        //If the image passed was not an image element then create one.
+        if (!(img instanceof HTMLImageElement))
+        {
+            //Create an image and wait for it to load.
+            img = new Image();
+            var promise = new Promise(resolve => {
+                img.onload = () => resolve();
+                img.onerror = () => resolve();
+            });
+            img.src = image;
+            await promise;
+        }
+
+        canvas.width = newWidth; // destination canvas size
+        canvas.height = canvas.width * img.height / img.width;
+
+        var currWidth = Math.floor(img.width * 0.5);
+        var currHeight = Math.floor(img.height * 0.5);
+
+        oc.width = currWidth;
+        oc.height = currHeight;
+
+        //Resize the image.
+        octx.drawImage(img, 0, 0, currWidth, currHeight);
+
+        while (currWidth * 0.5 > newWidth) {
+            currWidth = Math.floor(currWidth * 0.5);
+            currHeight = Math.floor(currHeight * 0.5);
+
+            octx.drawImage(oc, 0, 0, currWidth * 2, currHeight * 2, 0, 0, currWidth, currHeight);
+        }
+
+        //Put the final resized image onto the dest canvas.
+        ctx.drawImage(oc, 0, 0, currWidth, currHeight, 0, 0, canvas.width, canvas.height);
+
+        //Now sharpen the resized image
+        var w = canvas.width, h = canvas.height;
+        var x, sx, sy, r, g, b, a, dstOff, srcOff, wt, cx, cy, scy, scx,
+            weights = [0, -1, 0, -1, 5, -1, 0, -1, 0],
+            katet = Math.round(Math.sqrt(weights.length)),
+            half = (katet * 0.5) | 0,
+            dstData = ctx.createImageData(w, h),
+            dstBuff = dstData.data,
+            srcBuff = ctx.getImageData(0, 0, w, h).data,
+            y = h;
+    
+        while (y--) {
+            x = w;
+            while (x--) {
+                sy = y;
+                sx = x;
+                dstOff = (y * w + x) * 4;
+                r = 0;
+                g = 0;
+                b = 0;
+                a = 0;
+    
+                for (cy = 0; cy < katet; cy++) {
+                    for (cx = 0; cx < katet; cx++) {
+                        scy = sy + cy - half;
+                        scx = sx + cx - half;
+    
+                        if (scy >= 0 && scy < h && scx >= 0 && scx < w) {
+                            srcOff = (scy * w + scx) * 4;
+                            wt = weights[cy * katet + cx];
+    
+                            r += srcBuff[srcOff] * wt;
+                            g += srcBuff[srcOff + 1] * wt;
+                            b += srcBuff[srcOff + 2] * wt;
+                            a += srcBuff[srcOff + 3] * wt;
+                        }
+                    }
+                }
+    
+                dstBuff[dstOff] = r * sharpen + srcBuff[dstOff] * (1 - sharpen);
+                dstBuff[dstOff + 1] = g * sharpen + srcBuff[dstOff + 1] * (1 - sharpen);
+                dstBuff[dstOff + 2] = b * sharpen + srcBuff[dstOff + 2] * (1 - sharpen);
+                dstBuff[dstOff + 3] = srcBuff[dstOff + 3];
+            }
+        }
+    
+        //Put the sharpened image back onto the canvas.
+        ctx.putImageData(dstData, 0, 0);
+
+        //Get a blob from the canvas.
+        var promise = new Promise(resolve => {
+            canvas.toBlob(blob => resolve(blob), 'image/jpeg', 0.95);
+        });
+
+        //Await the creation of the blob and return it.
+        return await promise;
+    }
+}
+
+window.Aperture = Aperture;
+
+export { 
+    Aperture
+}