DrawString on WP7

I'm trying to develop something on WP7 (XAML not XNA) and 开发者_JAVA百科want to be able to draw text onto an image and then save that image with the text on it. Is there a library or function that already exists that does this or would I need to implement my own solution to draw every character?

There is no API in WP7 for rendering text to a bitmap image. The WP7 API for manipulating bitmap images is WriteableBitmap, which gives you an array of pixels and nothing more!

There is a good codeplex project WriteableBitmapEx, which adds various drawing extension methods, but not text rendering.

You can however place text above an image, for example ...

<Grid>
  <Image Source="myImage.png"/>
  <TextBlock Text="Overlay text"/>
<Grid>

This will render the text above the image.

You can also use a WriteableBitmap to 'capture' part of the visual tree into a bitmap, see my blog post for examples. The route you take really depends on your requirements.

I found a way of doing this by adding a Textblock onto the WriteableBitmap. This link gives you an example of how it can be achieved.

How can i write string on WriteableBitmap?