如何使用画布在Android的合并两个图像？ [英] How to use Canvas for merging two images in Android?

问题描述

我想通过重叠创造了两个不同的图像合成图像。

I want to create a combined image with two different images by overlapping.

有关本我的code是

  ImageView image = (ImageView) findViewById(R.id.imageView1);
  Drawable drawableFore = getResources().getDrawable(R.drawable.foreg);
  Drawable drawableBack = getResources().getDrawable(R.drawable.backg);

  Bitmap bitmapFore = ((BitmapDrawable) drawableFore).getBitmap();
  Bitmap bitmapBack = ((BitmapDrawable) drawableBack).getBitmap();

  Bitmap scaledBitmapFore = Bitmap.createScaledBitmap(bitmapFore, 35, 35, true);
  Bitmap scaledBitmapBack = Bitmap.createScaledBitmap(bitmapBack, 45, 45, true);

  Bitmap combineImages = overlay(scaledBitmapBack, scaledBitmapFore);

  image.setImageBitmap(combineImages);

覆盖（）方法

overlay() method is

public static Bitmap overlay(Bitmap bmp1, Bitmap bmp2)
{
 try
 {
   Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(),  bmp1.getConfig());
   Canvas canvas = new Canvas(bmOverlay);
   canvas.drawBitmap(bmp1, new Matrix(), null);
   canvas.drawBitmap(bmp2, 0, 0, null);
   return bmOverlay;
 } catch (Exception e)
 {
    // TODO: handle exception
  e.printStackTrace();
  return null;
 }
}

案例1：覆盖的方法在这种情况下返回null

case 1 :overlay method returns null in this case.

2的情况下。但是，当我切换图像，例如我用的背景图像中的前景和前景图像的背景设定的设置，然后code正常工作

case 2: But when I switch images like I use background image for setting in foreground and foreground image for setting in background then code works fine.

但我想第一种情况下应能正常工作，但事实并非如此。 我没有得到为什么会这样。

but I want the first case should work properly but it is not. I am not getting why this is happening.

请帮

推荐答案

我认为它发生的，因为第二位是个头大。因此，尝试这样的：

I think it happens, because the 2nd bitmap is bigger in size. So try this:

public static Bitmap overlay(Bitmap bmp1, Bitmap bmp2)
{
 try
 {
   int maxWidth = (bmp1.getWidth() > bmp2.getWidth() ? bmp1.getWidth() : bmp2.getWidth());
   int maxHeight = (bmp1.getHeight() > bmp2.getHeight() ? bmp1.getHeight() : bmp2.getHeight());
   Bitmap bmOverlay = Bitmap.createBitmap(maxWidth, maxHeight,  bmp1.getConfig());
   Canvas canvas = new Canvas(bmOverlay);
   canvas.drawBitmap(bmp1, 0, 0, null);
   canvas.drawBitmap(bmp2, 0, 0, null);
   return bmOverlay;

 } catch (Exception e)
 {
    // TODO: handle exception
  e.printStackTrace();
  return null;
 }
}

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