安卓：从位图裁剪位图，并设置为ImageView的SRC

我试图从一个spritesheet裁剪精灵，但是裁剪的图片是不是我指定的图像的一部分。安卓：从位图裁剪位图，并设置为ImageView的SRC

spritesheet包含大小为32 x 32像素的精灵，因此第一个精灵应该在像素0到32（水平）和0到32（垂直），假设最左上角的像素是[0,0 ]。

Bitmap spritesheet = BitmapFactory.decodeResource(getResources(), R.drawable.spritesheet_32x32); 
Bitmap sprite = Bitmap.createBitmap(spritesheet, 0, 0, 32, 32);

ImageView只是一个普通的ImageView，没有设置src，width或height。

ImageView view = (ImageView)findViewById(R.id.player1); 
view.setImageBitmap(sprite);

但显示的图像只是第一个精灵的一小部分。我怎么监督？是view.setImageBitmap(sprite);这个正确的方法？是否需要ImageView的设置位图前修复宽度和高度？

编辑：也许我应该对我的布局更加清晰。 LinearLayout上排列着两个ImageView。这里的XML：

<LinearLayout 
     android:orientation="horizontal" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent" 
     android:baselineAligned="false"> 
    <ImageView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:scaleX="-1" 
     android:id="@+id/player1" 
     android:layout_weight="1" 
     android:layout_gravity="center_vertical" /> 
    <ImageView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/player2" 
     android:layout_weight="1" 
     android:layout_gravity="center_vertical" /> 
</LinearLayout>

来源

2015-04-25 Cipher

http://stackoverflow.com/questions/18232034/how-can-i-crop-a-bitmap-for-imageview –

import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 

public class ImageResizer { 

public static Bitmap decodeSampledBitmapFromFile(String filename, 
    int reqWidth, int reqHeight) { 
// First decode with inJustDecodeBounds=true to check dimensions 
final BitmapFactory.Options 
     options = new BitmapFactory.Options(); 
options.inJustDecodeBounds = true; 
BitmapFactory.decodeFile(filename, options); 
// Calculate inSampleSize 
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); 
// Decode bitmap with inSampleSize set 
options.inJustDecodeBounds = false; 
return BitmapFactory.decodeFile(filename, options); 
} 

public static int calculateInSampleSize(BitmapFactory.Options options, 
    int reqWidth, int reqHeight) { 
// BEGIN_INCLUDE (calculate_sample_size) 
// Raw height and width of image 
final int height = options.outHeight; 
final int width = options.outWidth; 
int inSampleSize = 1; 

if (height > reqHeight || width > reqWidth) { 

    final int halfHeight = height/2; 
    final int halfWidth = width/2; 

    // Calculate the largest inSampleSize value that is a power of 2 and keeps both 
    // height and width larger than the requested height and width. 
    while ((halfHeight/inSampleSize) > reqHeight 
      && (halfWidth/inSampleSize) > reqWidth) { 
     inSampleSize *= 2; 
    } 

    // This offers some additional logic in case the image has a strange 
    // aspect ratio. For example, a panorama may have a much larger 
    // width than height. In these cases the total pixels might still 
    // end up being too large to fit comfortably in memory, so we should 
    // be more aggressive with sample down the image (=larger inSampleSize). 

    long totalPixels = width * height/inSampleSize; 

    // Anything more than 2x the requested pixels we'll sample down further 
    final long totalReqPixelsCap = reqWidth * reqHeight * 2; 

    while (totalPixels > totalReqPixelsCap) { 
     inSampleSize *= 2; 
     totalPixels /= 2; 
    } 
} 
return inSampleSize; 
// END_INCLUDE (calculate_sample_size) 
} 

}

呼叫我还没有尝试过的方法

Bitmap bmp = ImageResizer.decodeSampledBitmapFromFile(new File(filePath).getAbsolutePath(), 512, 342);

但如下可能工作传递方法的参数一样
imageView.getWidth（），ImageView的。 getHeight（）

来源

2015-04-25 10:54:29

我必须使用此方法设置ImageView的高度和宽度？现在，我只是路过的spritesheet的原始尺寸，结果看起来是一样的。 – Cipher

安卓：从位图裁剪位图，并设置为ImageView的SRC

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