Working with canvas

Question

I am able to draw a signature on my canvas. Now after that I want to save this signature as an image which can be used later.

I am unable to implement an onClicklistener on this canvas. Also I am unclear as to how this signature can be stored as an image. Please suggest?

score 2 · Answer 1 · answered Sep 20 '10 at 06:31

2

Try this:

Bitmap bmp = Bitmap.createBitmap(...);
Canvas can = new Canvas(bmp);

When you change your canvas, bitmap bmp will change too. Canvas is only raference to Bitmap canvas, and you have no need to save canvas. Save only Bitmap (bmp).

answered Sep 20 '10 at 06:31

Alexander Mikhaylov

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But how do i save bitmap to an Sd-card ? – NickHalden Sep 20 '10 at 10:29
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I think you neend to use compress(Bitmap.CompressFormat format, int quality, OutputStream stream) – Alexander Mikhaylov Sep 21 '10 at 05:10
This method will write bitmap to outputStream. After that write this output stream to file on sd card. – Alexander Mikhaylov Sep 21 '10 at 05:11
http://stackoverflow.com/questions/649154/android-bitmap-save-to-location - see that – Alexander Mikhaylov Sep 21 '10 at 05:13

score 0 · Answer 2 · answered Sep 16 '11 at 00:19

To save the canvas drawing as an image, you need to convert it to a data url using the toDataURL method. Once you have the data url, you can use it to set the source of an image element so the user can right click and download the image.:

// save canvas image as data url (png format by default)
var dataURL = canvas.toDataURL();

// set canvasImg image src to dataURL
// so it can be saved as an image
document.getElementById("canvasImg").src = dataURL;

Reference: http://www.html5canvastutorials.com/advanced/html5-canvas-save-drawing-as-an-image/

but android doesn't quite support `toDataURL` :( – gion_13 Mar 27 '12 at 14:43 — gion_13, Mar 27 '12 at 14:43

Working with canvas

2 Answers2