javascript - Canvas 响应式媒体屏幕最小宽度 - FabricJS

Question

我尝试为每个分辨率调整 Canvas ，所以我首先使用 css 并为每个分辨率放置媒体屏幕。

@media screen and (min-width: 320px) {
  #c {   -webkit-transform : scale(0.38);
-webkit-transform-origin : 0 0; }

https://jsfiddle.net/qj3oyzs8/

它对我有用，但所有对象都不能正确拖动、调整大小或旋转。 一种解决方案是应用 zoomOut 和 zoomIn，例如:

http://jsfiddle.net/Q3TMA/662/

现在我需要帮助了解如何在浏览器中正确打开 Canvas 缩放捕获分辨率

---

编辑

function screencan() {
   var widthscrencan = (window.innerWidth > 0) ? window.innerWidth : screen.width;

/*

In if has to have the same scale the css
@media screen and (min-width: 320px) {
  #c {   -webkit-transform : scale(0.38);
-webkit-transform-origin : 0 0; }
}


*/
    if(widthscrencan <= 360 ) {
           // Zoom Out


 function zoomOut() {
        // TODO limit max cavas zoom out

        canvasScale = canvasScale / SCALE_FACTOR;

        canvas.setHeight(canvas.getHeight() * (1 / SCALE_FACTOR));
        canvas.setWidth(canvas.getWidth() * (1 / SCALE_FACTOR));

        var objects = canvas.getObjects();
        for (var i in objects) {
            var scaleX = objects[i].scaleX;
            var scaleY = objects[i].scaleY;
            var left = objects[i].left;
            var top = objects[i].top;

            var tempScaleX = scaleX * (1 / SCALE_FACTOR);
            var tempScaleY = scaleY * (1 / SCALE_FACTOR);
            var tempLeft = left * (1 / SCALE_FACTOR);
            var tempTop = top * (1 / SCALE_FACTOR);

            objects[i].scaleX = tempScaleX;
            objects[i].scaleY = tempScaleY;
            objects[i].left = tempLeft;
            objects[i].top = tempTop;

            objects[i].setCoords();
        }

        canvas.renderAll();        
    }

    }               
 }
 window.onload = screencan;

没用

感谢您的帮助

Answer 1

快乐!!!我明白了:D

唯一的问题是浏览器移动了新的调整大小。需要刷新页面，因为window.onload = zoomIn;

解决方案!我删除了 css 的查询屏幕，并且:

widthscrencan = (window.innerWidth > 0) ? window.innerWidth : screen.width; // capture width screen onload
canvasScale = 1; //global  

   if (widthscrencan <=360){ 

      function zoomIn() {
          var SCALE_FACTOR = .37;
          canvasScale = canvasScale * SCALE_FACTOR;

      canvas.setHeight(canvas.getHeight() * SCALE_FACTOR);
      canvas.setWidth(canvas.getWidth() * SCALE_FACTOR);

      var objects = canvas.getObjects();
      for (var i in objects) {
          var scaleX = objects[i].scaleX;
          var scaleY = objects[i].scaleY;
          var left = objects[i].left;
          var top = objects[i].top;

          var tempScaleX = scaleX * SCALE_FACTOR;
          var tempScaleY = scaleY * SCALE_FACTOR;
          var tempLeft = left * SCALE_FACTOR;
          var tempTop = top * SCALE_FACTOR;

          objects[i].scaleX = tempScaleX;
          objects[i].scaleY = tempScaleY;
          objects[i].left = tempLeft;
          objects[i].top = tempTop;

          objects[i].setCoords();
      }


      canvas.renderAll();
      alert(widthscrencan+' function 360'); 

  }

   window.onload = zoomIn;
 }






   if ((widthscrencan >=361) || (widthscrencan ==768)){ 

            function zoomIn768() {
          var SCALE_FACTOR = .45;
          canvasScale = canvasScale * SCALE_FACTOR;

          canvas.setHeight(canvas.getHeight() * SCALE_FACTOR);
          canvas.setWidth(canvas.getWidth() * SCALE_FACTOR);

          var objects = canvas.getObjects();
          for (var i in objects) {
              var scaleX = objects[i].scaleX;
              var scaleY = objects[i].scaleY;
              var left = objects[i].left;
              var top = objects[i].top;

              var tempScaleX = scaleX * SCALE_FACTOR;
              var tempScaleY = scaleY * SCALE_FACTOR;
              var tempLeft = left * SCALE_FACTOR;
              var tempTop = top * SCALE_FACTOR;

              objects[i].scaleX = tempScaleX;
              objects[i].scaleY = tempScaleY;
              objects[i].left = tempLeft;
              objects[i].top = tempTop;

              objects[i].setCoords();
          }


          canvas.renderAll();
          alert(widthscrencan+' function 768'); 


        }
          window.onload = zoomIn768;
    }

   if ((widthscrencan >=769) || (widthscrencan ==992)){ 

            function zoomIn992() {
          var SCALE_FACTOR = .5;
          canvasScale = canvasScale * SCALE_FACTOR;

          canvas.setHeight(canvas.getHeight() * SCALE_FACTOR);
          canvas.setWidth(canvas.getWidth() * SCALE_FACTOR);

          var objects = canvas.getObjects();
          for (var i in objects) {
              var scaleX = objects[i].scaleX;
              var scaleY = objects[i].scaleY;
              var left = objects[i].left;
              var top = objects[i].top;

              var tempScaleX = scaleX * SCALE_FACTOR;
              var tempScaleY = scaleY * SCALE_FACTOR;
              var tempLeft = left * SCALE_FACTOR;
              var tempTop = top * SCALE_FACTOR;

              objects[i].scaleX = tempScaleX;
              objects[i].scaleY = tempScaleY;
              objects[i].left = tempLeft;
              objects[i].top = tempTop;

              objects[i].setCoords();
          }


          canvas.renderAll();
          alert(widthscrencan+' function 992'); 


        }
          window.onload = zoomIn992;
    }

      if ((widthscrencan >=993) || (widthscrencan ==1200)){ 

            function zoomIn1200() {
          var SCALE_FACTOR = .9;
          canvasScale = canvasScale * SCALE_FACTOR;

          canvas.setHeight(canvas.getHeight() * SCALE_FACTOR);
          canvas.setWidth(canvas.getWidth() * SCALE_FACTOR);

          var objects = canvas.getObjects();
          for (var i in objects) {
              var scaleX = objects[i].scaleX;
              var scaleY = objects[i].scaleY;
              var left = objects[i].left;
              var top = objects[i].top;

              var tempScaleX = scaleX * SCALE_FACTOR;
              var tempScaleY = scaleY * SCALE_FACTOR;
              var tempLeft = left * SCALE_FACTOR;
              var tempTop = top * SCALE_FACTOR;

              objects[i].scaleX = tempScaleX;
              objects[i].scaleY = tempScaleY;
              objects[i].left = tempLeft;
              objects[i].top = tempTop;

              objects[i].setCoords();
          }


          canvas.renderAll();
          alert(widthscrencan+' function 1200'); 


        }
          window.onload = zoomIn1200;
    }


      if (widthscrencan >=1300){ 

            function zoomIn1300() {
          var SCALE_FACTOR = 1.01;
          canvasScale = canvasScale * SCALE_FACTOR;

          canvas.setHeight(canvas.getHeight() * SCALE_FACTOR);
          canvas.setWidth(canvas.getWidth() * SCALE_FACTOR);

          var objects = canvas.getObjects();
          for (var i in objects) {
              var scaleX = objects[i].scaleX;
              var scaleY = objects[i].scaleY;
              var left = objects[i].left;
              var top = objects[i].top;

              var tempScaleX = scaleX * SCALE_FACTOR;
              var tempScaleY = scaleY * SCALE_FACTOR;
              var tempLeft = left * SCALE_FACTOR;
              var tempTop = top * SCALE_FACTOR;

              objects[i].scaleX = tempScaleX;
              objects[i].scaleY = tempScaleY;
              objects[i].left = tempLeft;
              objects[i].top = tempTop;

              objects[i].setCoords();
          }


          canvas.renderAll();
          alert(widthscrencan+' function 1300'); 


        }
          window.onload = zoomIn1300;
    }