[whatwg] Feature proposal - add method to CanvasRenderingContext2D
Hi, the subject says it all. Details follows. Description add overload of (or add similarly called) method createImageData to interface CanvasRenderingContext2D which would take two arguments: - encodedImageBinaryData - dataMimeType which are rather self explanatory. Reason The reason is to be able to supply output of the future File API standard (http://www.w3.org/TR/FileAPI/) into canvas. Use case Usually there is a lot of image processing during image upload. This processing takes place at the server and it can consume a lot of system resources. The method I propose would enable basic client side image processing by loading image to canvas tag. Then the modified image could be sent to server instead of the original one. This would save a lot of server's resources and sometimes even a lot of bandwidth. Another possibilities There are already solutions for this use case, but they are based on technologies like Flash or Silverlight. With this proposal, no plugin would be needed. -- František Řezáč Prague, Czech Republic
Re: [whatwg] Feature proposal - add method to CanvasRenderingContext2D
On Wed, Mar 3, 2010 at 1:08 PM, František Řezáč
frantisek.re...@calavera.info wrote:
Description
add overload of (or add similarly called) method createImageData to
interface CanvasRenderingContext2D which would take two arguments:
- encodedImageBinaryData
- dataMimeType
which are rather self explanatory.
Reason
The reason is to be able to supply output of the future File API
standard (http://www.w3.org/TR/FileAPI/) into canvas.
The canvas API already lets you do:
var img = new Image();
img.onload = function() {
ctx.drawImage(img, 0, 0);
// do processing on the canvas
};
img.src = 'data:image/png;base64,...'; // get this string from
readAsDataURL etc
Is that sufficient for your use case?
--
Philip Taylor
exc...@gmail.com
Re: [whatwg] Feature proposal - add method to CanvasRenderingContext2D
Yes, it works. I failed to spot that it's possible to put data url to
Image.src, sorry.
On Wed, Mar 3, 2010 at 3:33 PM, Philip Taylor excors+wha...@gmail.com wrote:
On Wed, Mar 3, 2010 at 1:08 PM, František Řezáč
frantisek.re...@calavera.info wrote:
Description
add overload of (or add similarly called) method createImageData to
interface CanvasRenderingContext2D which would take two arguments:
- encodedImageBinaryData
- dataMimeType
which are rather self explanatory.
Reason
The reason is to be able to supply output of the future File API
standard (http://www.w3.org/TR/FileAPI/) into canvas.
The canvas API already lets you do:
var img = new Image();
img.onload = function() {
ctx.drawImage(img, 0, 0);
// do processing on the canvas
};
img.src = 'data:image/png;base64,...'; // get this string from
readAsDataURL etc
Is that sufficient for your use case?
--
Philip Taylor
exc...@gmail.com
--
František Řezáč
Prague, Czech Republic
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