我创建了一个宽度为16且高度为16的画布.然后我使用WebGL渲染图像.这就是它的样子：

之后,我使用宽度：256px和高度：256px来缩放画布.我还将图像渲染设置为像素化：

      canvas {
        image-rendering: optimizeSpeed;             /* STOP SMOOTHING, GIVE ME SPEED  */
        image-rendering: -moz-crisp-edges;          /* Firefox                        */
        image-rendering: -o-crisp-edges;            /* Opera                          */
        image-rendering: -webkit-optimize-contrast; /* Chrome (and eventually Safari) */
        image-rendering: pixelated; /* Chrome */
        image-rendering: optimize-contrast;         /* CSS3 Proposed                  */
        -ms-interpolation-mode: nearest-neighbor;   /* IE8+                           */
        width: 256px;
        height: 256px;
      }

这是结果：

图像模糊.为什么？我在OSX Mojave上使用Safari 12.0.2.

解决方法:

Safari尚不支持图像渲染：像素化;在WebGL上. Filed a bug

脆边也不是！=像素化.清晰边缘可以是任何数量的算法.它并不意味着像素化.这意味着应用一些算法,保持清晰的边缘,其中有大量的算法.

The spec itself显示了示例：

鉴于此图片：

这是像素化的：

允许浏览器使用各种算法进行清晰边缘的情况,例如结果可能如此

换句话说,您的CSS可能无法产生您期望的结果.如果浏览器不支持像素化但支持清晰边缘,如果他们使用上面的算法,那么你将不会像素化的外观.

在没有图像渲染的情况下绘制像素化图形的最高效方法：像素化是绘制一个小纹理,然后使用NEAREST过滤将该纹理绘制到画布上.

const vs = `
attribute vec4 position;
void main() {
  gl_Position = position;
}
`;
const fs = `
precision mediump float;
void main() {
  gl_FragColor = vec4(1, 0, 0, 1);
}
`;

const screenVS = `
attribute vec4 position;
varying vec2 v_texcoord;
void main() {
  gl_Position = position;
  // because we know position goes from -1 to 1
  v_texcoord = position.xy * 0.5 + 0.5;
}
`;
const screenFS = `
precision mediump float;
varying vec2 v_texcoord;
uniform sampler2D u_tex;
void main() {
  gl_FragColor = texture2D(u_tex, v_texcoord);
}
`;

const gl = document.querySelector('canvas').getContext('webgl', {antialias: false});

// compile shaders, link programs, look up locations
const programInfo = twgl.createProgramInfo(gl, [vs, fs]);
const screenProgramInfo = twgl.createProgramInfo(gl, [screenVS, screenFS]);


const width = 16;
const height = 16;
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

const fb = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);

// create buffers and put data in
const quadBufferInfo = twgl.createBufferInfoFromArrays(gl, {
  position: { 
    numComponents: 2,
    data: [
      -1, -1, 
       1, -1,
      -1,  1,
      -1,  1, 
       1, -1,
       1,  1,
    ],
  }
});


render();

function render() {
  // draw at 16x16 to texture
  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
  gl.viewport(0, 0, width, height);
  gl.useProgram(programInfo.program);
  // bind buffers and set attributes
  twgl.setBuffersAndAttributes(gl, programInfo, quadBufferInfo);
  
  gl.drawArrays(gl.TRIANGLES, 0, 3);  // only draw the first triangle
  
  // draw texture to canvas
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
  gl.useProgram(screenProgramInfo.program);
  // bind buffers and set attributes
  twgl.setBuffersAndAttributes(gl, screenProgramInfo, quadBufferInfo);
  // uniforms default to 0 so in this simple case
  // no need to bind texture or set uniforms since
  // we only have 1 texture, it's on texture unit 0
  // and the uniform defaults to 0
  
  gl.drawArrays(gl.TRIANGLES, 0, 6);
}

<canvas width="256" height="256"></canvas>
<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>

注意：如果您正在渲染3D或由于某些其他原因需要深度缓冲区,则需要向帧缓冲区添加深度渲染缓冲附件.

请注意,optimizeSpeed也不是一个真正的选择.它已被长期弃用,并且像浏览器一样可以解释清晰边缘.