I tried this out and unfortunately it is not a good solution. AvoidXfermode is implemented very inefficiently such that each pixel is converted to 32 bits, run through an alpha calculation, and then converted back to 16 bits. Based on the documentation of the tolerance parameter I was hoping for a shorcut mode when it was set to 0 that simply did a compare and write with no conversions.
On Mar 24, 4:20 am, Tazzer <[email protected]> wrote: > A very interesting idea :) although I have my doubts that drawing with > AvoidXfermode is not slower then drawing with alpha. Especially when > drawing the complete background in this mode. If I have the time I > certainly would like to try it. I now have the alpha issue working > using the solution above. > > Cheers > > On Mar 23, 3:35 am, Sarnoth <[email protected]> wrote: > > > I have been frustrated by the lack of support for sprites, but I came > > up with an idea that is backwards (literally) but might work. I > > haven't tested it to make sure it works as expected or to evaluate its > > speed. If you try it yourself I would be interested in the results. > > > Use the same key color for all of your sprites. To draw a frame, clear > > the canvas to the key color. Then draw each sprite starting with the > > front most and ending with the back most, and finally draw the > > background image. When drawing use AvoidXfermode with opColor set to > > your key color, tolerance set to 0, and mode set to TARGET. Drawing > > bitmaps of format 565 (no alpha channel) is by far the fastest way to > > draw, so hopefully drawing color keyed bitmaps of this type will > > produce nice results. > > > On Mar 19, 2:23 am, Tazzer <[email protected]> wrote: > > > > Hi, > > > > I am working on a 2d library for creating a game including sprite > > > collisions, sorting and animation converting (.spr to Java classes/ > > > bmp's). > > > > At first I used png's with the background color being transparant (24 > > > bits png image) but I want to use 256 color bitmaps with the > > > background color being transparant. > > > > Is this possible to do color keying in android? I looked at several > > > other threads about this topic but the all ended without a solution. > > > > Also I am now using the canvas.drawBitmap to render my sprites, but > > > will using opengl be faster? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
