Databases
StackOverflow2013
Postsdbo
POfaster way to apply alpha to a jpeg in an android app?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POfaster way to apply alpha to a jpeg in an android app?
    primarykey
    data
    text
    <p>I started my android app using png files for objects that required alpha, but I quickly realized that the space required was simply too much. So, I wrote a program that took a png with alpha and created a b&amp;w alpha mask png file and a jpeg. This gives me a tremendous amount of space savings, but the speed is not great.</p> <p>The following is the code in my Android app which combines the jpg image (the origImgId in the code) and the png mask (the alphaImgId in the code).</p> <p>It works, but it's not fast. I already cache the result and I'm working on code which will load these images in the menu screen before the game starts, but it would be nice if there was a way to speed this up.</p> <p>Does anyone have any suggestions? Note that I modified the code slightly so as to make it easily understandable. In the game this is actually a sprite which loads the image on demand and caches the result. Here you just see the code for loading the images and applying the alpha.</p> <pre><code>public class BitmapDrawableAlpha { public BitmapDrawableAlpha(int origImgId, int alphaImgId) { this.origImgId = origImgId; this.alphaImgId = alphaImgId; } protected BitmapDrawable loadDrawable(Activity a) { Drawable d = a.getResources().getDrawable(origImgId); Drawable da = a.getResources().getDrawable(alphaImgId); Bitmap b = Bitmap.createBitmap(d.getIntrinsicWidth(),d.getIntrinsicHeight(),Bitmap.Config.ARGB_8888); { Canvas c = new Canvas(b); d.setBounds(0,0,d.getIntrinsicWidth()-1,d.getIntrinsicHeight()-1); d.draw(c); } Bitmap ba = Bitmap.createBitmap(d.getIntrinsicWidth(),d.getIntrinsicHeight(),Bitmap.Config.ARGB_8888); { Canvas c = new Canvas(ba); da.setBounds(0,0,d.getIntrinsicWidth()-1,d.getIntrinsicHeight()-1); da.draw(c); } applyAlpha(b,ba); return new BitmapDrawable(b); } /** Apply alpha to the specified bitmap b. */ public static void applyAlpha(Bitmap b, Bitmap bAlpha) { int w = b.getWidth(); int h = b.getHeight(); for(int y=0; y &lt; h; ++y) { for(int x=0; x &lt; w; ++x) { int pixel = b.getPixel(x,y); int finalPixel = Color.argb(Color.alpha(bAlpha.getPixel(x,y)), Color.red(pixel), Color.green(pixel), Color.blue(pixel)); b.setPixel(x,y,finalPixel); } } } private int origImgId; private int alphaImgId; } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USHappyEngineer
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POfaster way to apply alpha to a jpeg in an android app?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POfaster way to apply alpha to a jpeg in an android app?
      1. USJoxTraex
      1. VTFavorite
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload