canvas

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm trying to set zooming and panning limits on a control I found here: https://wpfextensions.codeplex.com I managed to set zooming limits, but now I'm having trouble setting the panning limits so that you can't pan the object inside the canvas, outside the view. I succeeded in setting the limits, but only when the zoom level is 1 ( Zoom == 1 , so no zoom), but the moment you increase the zoom (by rotating the mouse wheel) things start to go wrong : the limits are set, but they are not set

问题 I'm trying to set zooming and panning limits on a control I found here: https://wpfextensions.codeplex.com I managed to set zooming limits, but now I'm having trouble setting the panning limits so that you can't pan the object inside the canvas, outside the view. I succeeded in setting the limits, but only when the zoom level is 1 ( Zoom == 1 , so no zoom), but the moment you increase the zoom (by rotating the mouse wheel) things start to go wrong : the limits are set, but they are not set

问题 i made 2 deference size html canvas to drawing First canvas = width : 400px,height:200px Second canvas = width : 200px,height :100px Now when i drawing in first html canvas i send that coordinates(x1,y1,x2,y2) to second canvas. When first canvas coordinates send in second canvas it's not drawing in same place as first canvas. is there way to equal first canvas coordinates to second one without changing canvas width and height . ctx.beginPath(); ctx.lineWidth = 5; ctx.lineCap = 'round'; ctx

问题 i made 2 deference size html canvas to drawing First canvas = width : 400px,height:200px Second canvas = width : 200px,height :100px Now when i drawing in first html canvas i send that coordinates(x1,y1,x2,y2) to second canvas. When first canvas coordinates send in second canvas it's not drawing in same place as first canvas. is there way to equal first canvas coordinates to second one without changing canvas width and height . ctx.beginPath(); ctx.lineWidth = 5; ctx.lineCap = 'round'; ctx

问题 I have a canvas HTML5 drawing pad. I would like to create a button with an undo function. How can I do it? My idea was to have one array stack. Anytime you draw and release the mouse, it saves the canvas image to the undo array stack by push. But as I tried it, it doesn't really work... Is there a better idea? Thank you in advance! var canvas = document.getElementById('paint'); var ctx = canvas.getContext('2d'); var sketch = document.getElementById('sketch'); var sketch_style =

问题 The image is captured from a DIV using HTML2CANVAS, but the image quality is very poor and it pixalets. The captured image resolution is 96 dpi, how to increase the resolution ? Is there any way to get a good quality image with high resolution, please help me out. My Code : <div style="border-style: solid; height: 15cm; width: 15cm; border-radius:25px; position: relative; top: 1px;" id="DIV1"> var element = $("#DIV1"); html2canvas(element, { useCORS: true, onrendered: function (canvas) { var