我有一个位图采取的Base64字符串从我的远程数据库，(encodedImage是字符串表示图像与Base64):
profileImage = (ImageView)findViewById(R.id.profileImage);
byte[] imageAsBytes=null;
try {
imageAsBytes = Base64.decode(encodedImage.getBytes());
} catch (IOException e) {e.printStackTrace();}
profileImage.setImageBitmap(
BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
);
profileImage是我的ImageView
但在显示在布局的ImageView中之前，我需要调整图像的大小。我得把它调整到120x120。
有人能告诉我调整大小的代码吗?
我发现的例子不能应用于base64字符串获得位图。
当前回答
有人问在这种情况下如何保持纵横比:
计算用于缩放的因子，并将其用于两个维度。 假设你想要一个图像的高度是屏幕的20%
int scaleToUse = 20; // this will be our percentage
Bitmap bmp = BitmapFactory.decodeResource(
context.getResources(), R.drawable.mypng);
int sizeY = screenResolution.y * scaleToUse / 100;
int sizeX = bmp.getWidth() * sizeY / bmp.getHeight();
Bitmap scaled = Bitmap.createScaledBitmap(bmp, sizeX, sizeY, false);
为了获得屏幕分辨率，你有这样的解决方案: 以像素为单位获取屏幕尺寸
其他回答
缩放位图的目标最大大小和宽度，同时保持纵横比:
int maxHeight = 2000;
int maxWidth = 2000;
float scale = Math.min(((float)maxHeight / bitmap.getWidth()), ((float)maxWidth / bitmap.getHeight()));
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
import android.graphics.Matrix
public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);
// "RECREATE" THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(
bm, 0, 0, width, height, matrix, false);
bm.recycle();
return resizedBitmap;
}
编辑:根据@aveschini的建议，我添加了bm.recycle();为了避免内存泄漏。请注意，如果您将前一个对象用于其他用途，则应相应地处理。
public static Bitmap resizeBitmapByScale(
Bitmap bitmap, float scale, boolean recycle) {
int width = Math.round(bitmap.getWidth() * scale);
int height = Math.round(bitmap.getHeight() * scale);
if (width == bitmap.getWidth()
&& height == bitmap.getHeight()) return bitmap;
Bitmap target = Bitmap.createBitmap(width, height, getConfig(bitmap));
Canvas canvas = new Canvas(target);
canvas.scale(scale, scale);
Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.DITHER_FLAG);
canvas.drawBitmap(bitmap, 0, 0, paint);
if (recycle) bitmap.recycle();
return target;
}
private static Bitmap.Config getConfig(Bitmap bitmap) {
Bitmap.Config config = bitmap.getConfig();
if (config == null) {
config = Bitmap.Config.ARGB_8888;
}
return config;
}
位图调整基于任何显示大小
public Bitmap bitmapResize(Bitmap imageBitmap) {
Bitmap bitmap = imageBitmap;
float heightbmp = bitmap.getHeight();
float widthbmp = bitmap.getWidth();
// Get Screen width
DisplayMetrics displaymetrics = new DisplayMetrics();
this.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
float height = displaymetrics.heightPixels / 3;
float width = displaymetrics.widthPixels / 3;
int convertHeight = (int) hight, convertWidth = (int) width;
// higher
if (heightbmp > height) {
convertHeight = (int) height - 20;
bitmap = Bitmap.createScaledBitmap(bitmap, convertWidth,
convertHighet, true);
}
// wider
if (widthbmp > width) {
convertWidth = (int) width - 20;
bitmap = Bitmap.createScaledBitmap(bitmap, convertWidth,
convertHeight, true);
}
return bitmap;
}
变化:
profileImage.setImageBitmap(
BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
To:
Bitmap b = BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
profileImage.setImageBitmap(Bitmap.createScaledBitmap(b, 120, 120, false));
