Android之图片工具类ImageUtil

package com.android.myimageutil;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.Drawable;

public class ImageUtil {

/**
*  放大缩小图片
* @param bitmap 要放大的图片
* @param dstWidth 目标宽
* @param dstHeight 目标高
* @return
*/
public static Bitmap zoomBitmap(Bitmap bitmap, int dstWidth, int dstHeight) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
Matrix matrix = new Matrix();
float scaleWidht = ((float) dstWidth / width);
float scaleHeight = ((float) dstHeight / height);
matrix.postScale(scaleWidht, scaleHeight);
Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height,
matrix, true);
return newbmp;
}

/**
* 将Drawable转化为Bitmap
* @param drawable
* @return
*/
public static Bitmap drawableToBitmap(Drawable drawable) {
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, width, height);
drawable.draw(canvas);
return bitmap;

}

/**
* 获得圆角图片的方法
* @param bitmap
* @param roundPx  4脚幅度
* @return
*/
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {

Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);

final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);

paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);

return output;
}

/**
* 获得带倒影的图片方法
* @param bitmap
* @return
*/
public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) {
final int reflectionGap = 4;
int width = bitmap.getWidth();
int height = bitmap.getHeight();

Matrix matrix = new Matrix();
matrix.preScale(1, -1);

Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,
width, height / 2, matrix, false);

Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);

Canvas canvas = new Canvas(bitmapWithReflection);
canvas.drawBitmap(bitmap, 0, 0, null);
Paint deafalutPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, deafalutPaint);

canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
0x00ffffff, TileMode.CLAMP);
paint.setShader(shader);
// Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
// Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);

return bitmapWithReflection;
}

/**
* 添加文字到图片，类似水印文字。
* @param gContext
* @param gResId
* @param gText
* @return
*/
public static Bitmap drawTextToBitmap(Context gContext, int gResId, String gText) {
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap = BitmapFactory.decodeResource(resources, gResId);

android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();
// set default bitmap config if none
if (bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);

Canvas canvas = new Canvas(bitmap);
// new antialised Paint
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.rgb(61, 61, 61));
// text size in pixels
paint.setTextSize((int) (14 * scale*5));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);

// draw text to the Canvas center
Rect bounds = new Rect();
paint.getTextBounds(gText, 0, gText.length(), bounds);

//draw  text  to the bottom
int x = (bitmap.getWidth() - bounds.width())/10*9 ;
int y = (bitmap.getHeight() + bounds.height())/10*9;
canvas.drawText(gText, x , y, paint);

return bitmap;
}

}