从原始位图剪切图像
Posted 马骝
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了从原始位图剪切图像相关的知识，希望对你有一定的参考价值。
public static Bitmap createBitmap (Bitmap source, int x, int y, int width, int height, Matrix m, boolean filter)
从原始位图剪切图像，这是一种高级的方式。可以用Matrix(矩阵)来实现旋转等高级方式截图
参数说明：
Bitmap source：要从中截图的原始位图
int x:起始x坐标
int y：起始y坐标
int width：要截的图的宽度
int height：要截的图的宽度
Bitmap.Config config：一个枚举类型的配置，可以定义截到的新位图的质量
返回值：返回一个剪切好的Bitmap
三、Bitmap剪切的封装
实际使用中，因为项目需要时常需要对基本功能进行封装，下面是一段封装的代码，仅供参考。
import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PorterDuff; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.RectF; public class BitmapCut { /** * 通过资源id转化成Bitmap * * @param context * @param resId * @return */ public static Bitmap ReadBitmapById(Context context, int resId) { BitmapFactory.Options opt = new BitmapFactory.Options(); opt.inPreferredConfig = Bitmap.Config.RGB_565; opt.inPurgeable = true; opt.inInputShareable = true; InputStream is = context.getResources().openRawResource(resId); return BitmapFactory.decodeStream(is, null, opt); } /** * 设置背景为圆角 * * @param bitmap * @param pixels * @return */ public static Bitmap removeYuanjiao(Bitmap bitmap, int pixels) { int width = bitmap.getWidth(); int height = bitmap.getHeight(); Bitmap creBitmap = Bitmap.createBitmap(width, height, android.graphics.Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(creBitmap); Paint paint = new Paint(); float roundPx = pixels; RectF rectF = new RectF(0, 0, bitmap.getWidth() - pixels, bitmap.getHeight() - pixels); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); canvas.drawBitmap(bitmap, 0, 0, paint); if (!bitmap.isRecycled()) bitmap.recycle(); return creBitmap; } /** * 按正方形裁切图片 */ public static Bitmap ImageCrop(Bitmap bitmap, boolean isRecycled) { if (bitmap == null) { return null; } int w = bitmap.getWidth(); // 得到图片的宽，高 int h = bitmap.getHeight(); int wh = w > h ? h : w;// 裁切后所取的正方形区域边长 int retX = w > h ? (w - h) / 2 : 0;// 基于原图，取正方形左上角x坐标 int retY = w > h ? 0 : (h - w) / 2; Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, wh, wh, null, false); if (isRecycled && bitmap != null && !bitmap.equals(bmp) && !bitmap.isRecycled()) { bitmap.recycle(); bitmap = null; } // 下面这句是关键 return bmp;// Bitmap.createBitmap(bitmap, retX, retY, wh, wh, null, // false); } /** * 按长方形裁切图片 * * @param bitmap * @return */ public static Bitmap ImageCropWithRect(Bitmap bitmap) { if (bitmap == null) { return null; } int w = bitmap.getWidth(); // 得到图片的宽，高 int h = bitmap.getHeight(); int nw, nh, retX, retY; if (w > h) { nw = h / 2; nh = h; retX = (w - nw) / 2; retY = 0; } else { nw = w / 2; nh = w; retX = w / 4; retY = (h - w) / 2; } // 下面这句是关键 Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, false); if (bitmap != null && !bitmap.equals(bmp) && !bitmap.isRecycled()) { bitmap.recycle(); bitmap = null; } return bmp;// Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, // false); } /** * Bitmap --> byte[] * * @param bmp * @return */ public static byte[] readBitmap(Bitmap bmp) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bmp.compress(Bitmap.CompressFormat.JPEG, 60, baos); try { baos.flush(); baos.close(); } catch (IOException e) { e.printStackTrace(); } return baos.toByteArray(); } /** * 将图像裁剪成圆形 * * @param bitmap * @return */ public static Bitmap toRoundBitmap(Bitmap bitmap) { if (bitmap == null) { return null; } int width = bitmap.getWidth(); int height = bitmap.getHeight(); float roundPx; float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom; if (width <= height) { roundPx = width / 2; top = 0; bottom = width; left = 0; right = width; height = width; dst_left = 0; dst_top = 0; dst_right = width; dst_bottom = width; } else { roundPx = height / 2; float clip = (width - height) / 2; left = clip; right = width - clip; top = 0; bottom = height; width = height; dst_left = 0; dst_top = 0; dst_right = height; dst_bottom = height; } Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect src = new Rect((int) left, (int) top, (int) right, (int) bottom); final Rect dst = new Rect((int) dst_left, (int) dst_top, (int) dst_right, (int) dst_bottom); final RectF rectF = new RectF(dst); 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, src, dst, paint); if (bitmap != null && !bitmap.isRecycled()) { bitmap.recycle(); bitmap = null; } return output; } // 将图片变成带圆边的圆形图片 public static Bitmap getRoundBitmap(Bitmap bitmap, int width, int height) { if (bitmap == null) { return null; } // 将图片变成圆角 Bitmap roundBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); Canvas canvas = new Canvas(roundBitmap); Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); int len = (width > height) ? height : width; canvas.drawCircle(width / 2, height / 2, len / 2 - 8, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, true); canvas.drawBitmap(scaledBitmap, 0, 0, paint); // 将图片加圆边 Bitmap outBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); canvas = new Canvas(outBitmap); paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(0xffffffff); canvas.drawCircle(width / 2, height / 2, len / 2 - 4, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_OVER)); canvas.drawBitmap(roundBitmap, 0, 0, paint); bitmap.recycle(); bitmap = null; roundBitmap.recycle(); roundBitmap = null; scaledBitmap.recycle(); scaledBitmap = null; return outBitmap; } // 将图片变成带圆边的圆形图片 public static Bitmap getRoundBitmap(Bitmap bitmap, int width, int height, int color) { if (bitmap == null) { return null; } // 将图片变成圆角 Bitmap roundBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); Canvas canvas = new Canvas(roundBitmap); Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); int len = (width > height) ? height : width; canvas.drawCircle(width / 2, height / 2, len / 2 - 8, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, true); canvas.drawBitmap(scaledBitmap, 0, 0, paint); // 将图片加圆边 Bitmap outBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); canvas = new Canvas(outBitmap); paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(color); canvas.drawCircle(width / 2, height / 2, len / 2 - 4, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_OVER)); canvas.drawBitmap(roundBitmap, 0, 0, paint); bitmap.recycle(); bitmap = null; roundBitmap.recycle(); roundBitmap = null; scaledBitmap.recycle(); scaledBitmap = null; return outBitmap; } /** * function:图片转圆角 * * @param bitmap * 需要转的bitmap * @param pixels * 转圆角的弧度 * @return 转圆角的bitmap */ public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) { 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); final float roundPx = pixels; 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); if (bitmap != null && !bitmap.isRecycled()) { bitmap.recycle(); } return output; } /** * 获取指定的圆角图片 * * @param bitmap * @return */ public static Bitmap getRadiusBitmap(Bitmap bitmap) { Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(0xffffffff); Bitmap radiusBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); Canvas canvas = new Canvas(radiusBitmap); RectF rectF = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight()); canvas.drawRoundRect(rectF, 7, 7, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, 0, 0, paint); if (bitmap != null && !bitmap.isRecycled()) { bitmap.recycle(); } return radiusBitmap; } // 获得指定大小的圆边的bitmap数组 public static ArrayList<Bitmap> getRadiusBitmapList(String[] pathArray, int size, int len, float radius, int color) { Bitmap canvasBitmap = null; Canvas canvas = null; Paint paint = null; RectF rectF = new RectF(0, 0, len - radius, len - radius); File file = null; FileInputStream fis = null; Bitmap bitmap = null; Bitmap scaledBitmap = null; ArrayList<Bitmap> list = new ArrayList<Bitmap>(); for (int i = 0; i < pathArray.length; i++) { file = new File(pathArray[i]); if (!file.exists()) continue; try { fis = new FileInputStream(file); bitmap = BitmapFactory.decodeStream(fis); if (bitmap != null) { canvasBitmap = Bitmap.createBitmap(len, len, Config.ARGB_8888); canvas = new Canvas(canvasBitmap); paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(color); canvas.drawRoundRect(rectF, radius, radius, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, true); canvas.drawBitmap(scaledBitmap, 0, 0, paint); list.add(canvasBitmap); } } catch (FileNotFoundException e) { } finally { if (fis != null) { try { fis.close(); } catch (IOException e1) { } } } if (list.size() == size) break; } if (scaledBitmap != null && !scaledBitmap.isRecycled()) { scaledBitmap.recycle(); scaledBitmap = null; } if (bitmap != null && !bitmap.isRecycled()) { bitmap.recycle(); bitmap = null; } return list; } /** * 按照一定的宽高比例裁剪图片 * * @param bitmap * @param num1 * 长边的比例 * @param num2 * 短边的比例 * @return */ public static Bitmap ImageCrop(Bitmap bitmap, int num1, int num2, boolean isRecycled) { if (bitmap == null) { return null; } int w = bitmap.getWidth(); // 得到图片的宽，高 int h = bitmap.getHeight(); int retX, retY; int nw, nh; if (w > h) { if (h > w * num2 / num1) { nw = w; nh = w * num2 / num1; retX = 0; retY = (h - nh) / 2; } else { nw = h * num1 / num2; nh = h; retX = (w - nw) / 2; retY = 0; } } else { if (w > h * num2 / num1) { nh = h; nw = h * num2 / num1; retY = 0; retX = (w - nw) / 2; } else { nh = w * num1 / num2; nw = w; retY = (h - nh) / 2; retX = 0; } } Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, false); if (isRecycled && bitmap != null && !bitmap.equals(bmp) && !bitmap.isRecycled()) { bitmap.recycle(); bitmap = null; } return bmp;// Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, // false); } }
以上是关于从原始位图剪切图像的主要内容，如果未能解决你的问题，请参考以下文章
如何使用javascript修复HTML画布对象中的扭曲/扭曲和剪切图像？