[英]HTML5 canvas toDataURL not working with an image on the canvas
我想做的是將本地保存的圖像繪制到畫布上。 然后,我想將該畫布轉換為png圖像。 該圖像加載到畫布上,但是我創建的png圖像為空白。 有誰知道如何解決這一問題?
<!DOCTYPE html> <html> <head> </head> <body> <img src="" id="canvasImage" /> <canvas id="canvasId" width="160" height="145"></canvas> <script> var canvas = document.getElementById('canvasId'); var context = canvas.getContext("2d"); image = new Image(); image.src = "images/rightarrow.png"; image.onload = function(){ context.drawImage(image, 0, 0); } var imgTag = canvas.toDataURL("image/png"); document.getElementById("canvasImage").src = imgTag; </script> </body> </html>
您需要在onload
處理程序中創建映像
image = new Image();
image.src = "images/rightarrow.png";
image.onload = function(){
context.drawImage(image, 0, 0);
var imgTag = canvas.toDataURL("image/png");
document.getElementById("canvasImage").src = imgTag;
}
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