1 function ImageData(arr, width, height) { 2 if (!width || height === 0) { 3 throw 'invalid dimensions, width and height must be non-zero'; 4 } 5 if (arr.length % 4) { 6 throw 'arr must be a multiple of 4'; 7 } 8 height = height || arr.length/(4*width); 9 10 Object.defineProperty(this, 'data', { 11 value: arr, 12 writable: false 13 }); 14 Object.defineProperty(this, 'height', { 15 value: height, 16 writable: false 17 }); 18 Object.defineProperty(this, 'width', { 19 value: width, 20 writable: false 21 }); 22 } 23 24 CanvasKit.ImageData = function() { 25 if (arguments.length === 2) { 26 var width = arguments[0]; 27 var height = arguments[1]; 28 var byteLength = 4 * width * height; 29 return new ImageData(new Uint8ClampedArray(byteLength), 30 width, height); 31 } else if (arguments.length === 3) { 32 var arr = arguments[0]; 33 if (arr.prototype.constructor !== Uint8ClampedArray ) { 34 throw 'bytes must be given as a Uint8ClampedArray'; 35 } 36 var width = arguments[1]; 37 var height = arguments[2]; 38 if (arr % 4) { 39 throw 'bytes must be given in a multiple of 4'; 40 } 41 if (arr % width) { 42 throw 'bytes must divide evenly by width'; 43 } 44 if (height && (height !== (arr / (width * 4)))) { 45 throw 'invalid height given'; 46 } 47 height = arr / (width * 4); 48 return new ImageData(arr, width, height); 49 } else { 50 throw 'invalid number of arguments - takes 2 or 3, saw ' + arguments.length; 51 } 52 }
