图片处理常用方法总结

1. 高斯模式处理

查考笔记"高斯模式"部分,有专门总结

2.裁剪图片(按屏幕比例)

下面这个方法是将传入的bitmap(当初写这个方法的时候是取得系统壁纸)根据屏幕尺寸来裁剪

public Bitmap setAndcropWallpaper(Context context,Bitmap wallpaper) {
Bitmap targetBitmap = null;
if (wallpaper != null) {
try {
int wallpaperWidth = wallpaper.getWidth();
int wallpaperHeight = wallpaper.getHeight();
DisplayMetrics dm = new DisplayMetrics();
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
wm.getDefaultDisplay().getMetrics(dm);
int screenWidth = dm.widthPixels;// 1080
int screenHeight = dm.heightPixels;// 1920
float defaultScreen =  (float)screenHeight / (float)screenWidth;
Log.d(TAG, "defaultScreen=" + defaultScreen);
if (defaultScreen < 1) {
defaultScreen = (float)screenWidth / (float)screenHeight;
}
float bitmapSize = (float)wallpaperHeight /(float)wallpaperWidth;
int disWidth = 0;
int disHeight = 0;
int captureBitmapWidth = wallpaperWidth;
int captureBitmapHeight = wallpaperHeight;
Log.d(TAG, "defaultScreen=" + defaultScreen + " bitmapSize="
+ bitmapSize);
if (defaultScreen > bitmapSize) { // bitmapHeight is min ,  capture bitmapWidth
captureBitmapWidth = (int) ((screenWidth * wallpaperHeight) / screenHeight);
disWidth = wallpaperWidth - captureBitmapWidth;
} else if (defaultScreen < bitmapSize) {
captureBitmapHeight = (int) ((wallpaperWidth * screenHeight) / screenWidth);
disHeight = wallpaperHeight - captureBitmapHeight;
}
if (DEBUG) {
Log.d(TAG, "setAndcropWallpaper ----- disWidth="
+ disWidth + ",disHeight=" + disHeight
+ ",captureBitmapWidth=" + captureBitmapWidth
+ ",captureBitmapHeight=" + captureBitmapHeight
+ " screenWidth=" + screenWidth + " screenHeight="
+ screenHeight);
}
if (disWidth < 0 || disHeight < 0) {
return null;
}
targetBitmap = Bitmap.createBitmap(wallpaper, disWidth / 2,
disHeight / 2, captureBitmapWidth, captureBitmapHeight);
float scaleWidth = (float) ((float) captureBitmapWidth / screenWidth);
float scaleHeight = (float) ((float) captureBitmapHeight / screenHeight);
Log.d(TAG, "scaleWidth=" + scaleWidth + " scaleHeight="
+ scaleHeight);
if ((targetBitmap != null)
&& (scaleWidth != 1 || scaleHeight != 1)) {
Matrix matrix = new Matrix();
/**
 * 处理之后的图片小于屏幕尺寸 处理原始的图片比例和屏幕比例是一致,但尺寸比屏幕大
 */
if (scaleWidth != 0.0f && scaleHeight != 0.0f
&& (scaleWidth != 1.0f || scaleHeight != 1.0f)) {//
scaleWidth = 1.0f / scaleWidth;
scaleHeight = 1.0f / scaleHeight;
Log.d(TAG, "---scaleWidth=" + scaleWidth + " scaleHeight=" + scaleHeight);
}
matrix.postScale(scaleWidth, scaleHeight);
int width = targetBitmap.getWidth();
int height = targetBitmap.getHeight();
Log.d(TAG, "---width=" + width + " height=" + height);
targetBitmap = Bitmap.createBitmap(targetBitmap, 0, 0,
screenWidth > width ? width : screenWidth,
screenHeight > height ? height : screenHeight,
matrix, true);
}
} catch (OutOfMemoryError e) {
e.printStackTrace();
}
}
return targetBitmap;
}