我想为HTML Canvas创建自己的过滤器。代码如下。我收到错误：
无法执行＆＃39; putImageData＆＃39; on＆＃39; CanvasRenderingContext2D＆＃39;：参数1的类型不是＆＃39; ImageData＆＃39;
但是，如果我使用
更改SELECT ActualName,
lower(regexp_replace(column_name, E'([A-Z])', E'\_\\1','g')) As corrected_name
FROM Tablename
末尾的return outputData;
filter(input, values){}
一切正常，但我想，for (let i = 0; i < outputData.length; i++){
inputData[i] = outputData[i];
}返回值。我怎么能这样做？
filter(input, values){}//////////////////////////////
// Distortion Filter //
// Originally by JoelBesada //
//////////////////////////////
class FilterDistortion {
constructor() {
this.name = 'Distortion';
this.defaultValues = {
size: 4,
density: 0.5,
mix: 0.5,
};
this.valueRanges = {
size: { min: 1, max: 10 },
density: { min: 0.0, max: 1.0 },
mix: { min: 0.0, max: 1.0 },
};
}
filter(input, values = this.defaultValues) {
const { width, height } = input;
const inputData = input.data;
const outputData = inputData.slice();
let size = (values.size === undefined)
? this.defaultValues.size
: parseInt(values.size, 10);
if (size < 1) size = 1;
const density = (values.density === undefined)
? this.defaultValues.density
: Number(values.density);
const mix = (values.mix === undefined)
? this.defaultValues.mix
: Number(values.mix);
const radius = size + 1;
const numShapes = parseInt(((((2 * density) / 30) * width) * height) / 2, 10);
for (let i = 0; i < numShapes; i++) {
const sx = (Math.random() * (2 ** 32) & 0x7fffffff) % width;
const sy = (Math.random() * (2 ** 32) & 0x7fffffff) % height;
const rgb2 = [
inputData[(((sy * width) + sx) * 4) + 0],
inputData[(((sy * width) + sx) * 4) + 1],
inputData[(((sy * width) + sx) * 4) + 2],
inputData[(((sy * width) + sx) * 4) + 3],
];
for (let x = sx - radius; x < sx + radius + 1; x++) {
for (let y = sy - radius; y < sy + radius + 1; y++) {
if (x >= 0 && x < width && y >= 0 && y < height) {
const rgb1 = [
outputData[(((y * width) + x) * 4) + 0],
outputData[(((y * width) + x) * 4) + 1],
outputData[(((y * width) + x) * 4) + 2],
outputData[(((y * width) + x) * 4) + 3],
];
const mixedRGB = this.mixColors(mix, rgb1, rgb2);
for (let k = 0; k < 3; k++) {
outputData[(((y * width) + x) * 4) + k] = mixedRGB[k];
}
}
}
}
}
return outputData;
}
linearInterpolate(t, a, b) {
return a + (t * (b - a));
}
mixColors(t, rgb1, rgb2) {
const r = this.linearInterpolate(t, rgb1[0], rgb2[0]);
const g = this.linearInterpolate(t, rgb1[1], rgb2[1]);
const b = this.linearInterpolate(t, rgb1[2], rgb2[2]);
const a = this.linearInterpolate(t, rgb1[3], rgb2[3]);
return [r, g, b, a];
}
}
/////////////////
// Driver Code //
/////////////////
var img = new Image(); img.onload = draw; img.src = "//i.imgur.com/Kzz84cr.png";
function draw() {
c.width = this.width; c.height = this.height;
var ctx = c.getContext("2d");
// main loop
ctx.drawImage(this, 0, 0); // draw video frame
var data = ctx.getImageData(0, 0, c.width, c.height);
ctx.putImageData(new FilterDistortion().filter(data), 0, 0);
ctx.globalCompositeOperation = "source-over"; // "reset"
// rinse, repeat
}
答案 0 :(得分：1)
错误消息说明了这一切，您需要传递ImageData作为putImageData的第一个参数。
在这里你传递一个UInt8ClampedArray。
因此，您必须从此TypedArray创建new ImageData（当ImageData构造函数可用时），或者从画布上下文创建create an empty ImageData，然后设置其所有.data' s值为新值。
//////////////////////////////
// Distortion Filter //
// Originally by JoelBesada //
//////////////////////////////
class FilterDistortion {
constructor() {
this.name = 'Distortion';
this.defaultValues = {
size: 4,
density: 0.5,
mix: 0.5,
};
this.valueRanges = {
size: { min: 1, max: 10 },
density: { min: 0.0, max: 1.0 },
mix: { min: 0.0, max: 1.0 },
};
}
filter(input, values = this.defaultValues) {
const { width, height } = input;
const inputData = input.data;
const outputData = inputData.slice();
let size = (values.size === undefined)
? this.defaultValues.size
: parseInt(values.size, 10);
if (size < 1) size = 1;
const density = (values.density === undefined)
? this.defaultValues.density
: Number(values.density);
const mix = (values.mix === undefined)
? this.defaultValues.mix
: Number(values.mix);
const radius = size + 1;
const numShapes = parseInt(((((2 * density) / 30) * width) * height) / 2, 10);
for (let i = 0; i < numShapes; i++) {
const sx = (Math.random() * (2 ** 32) & 0x7fffffff) % width;
const sy = (Math.random() * (2 ** 32) & 0x7fffffff) % height;
const rgb2 = [
inputData[(((sy * width) + sx) * 4) + 0],
inputData[(((sy * width) + sx) * 4) + 1],
inputData[(((sy * width) + sx) * 4) + 2],
inputData[(((sy * width) + sx) * 4) + 3],
];
for (let x = sx - radius; x < sx + radius + 1; x++) {
for (let y = sy - radius; y < sy + radius + 1; y++) {
if (x >= 0 && x < width && y >= 0 && y < height) {
const rgb1 = [
outputData[(((y * width) + x) * 4) + 0],
outputData[(((y * width) + x) * 4) + 1],
outputData[(((y * width) + x) * 4) + 2],
outputData[(((y * width) + x) * 4) + 3],
];
const mixedRGB = this.mixColors(mix, rgb1, rgb2);
for (let k = 0; k < 3; k++) {
outputData[(((y * width) + x) * 4) + k] = mixedRGB[k];
}
}
}
}
}
return outputData;
}
linearInterpolate(t, a, b) {
return a + (t * (b - a));
}
mixColors(t, rgb1, rgb2) {
const r = this.linearInterpolate(t, rgb1[0], rgb2[0]);
const g = this.linearInterpolate(t, rgb1[1], rgb2[1]);
const b = this.linearInterpolate(t, rgb1[2], rgb2[2]);
const a = this.linearInterpolate(t, rgb1[3], rgb2[3]);
return [r, g, b, a];
}
}
/////////////////
// Driver Code //
/////////////////
var img = new Image(); img.crossOrigin=1; img.onload = draw; img.src = "//i.imgur.com/Kzz84cr.png";
function draw() {
c.width = this.width; c.height = this.height;
var ctx = c.getContext("2d");
// main loop
ctx.drawImage(this, 0, 0); // draw video frame
var data = ctx.getImageData(0, 0, c.width, c.height);
var distortedData = new FilterDistortion().filter(data);
var distortedImg;
try{
distortedImg = new window.ImageData(distortedData, c.width, c.height);
}
catch(e) {
distortedImg = ctx.createImageData(c.width, c.height);
distortedImg.data.set(distortedData);
}
ctx.putImageData(distortedImg, 0, 0);
ctx.globalCompositeOperation = "source-over"; // "reset"
// rinse, repeat
}<canvas id=c></canvas>