Java android裁剪图像,扩展为原始裁剪
我想在android上展示一个裁剪过的图像,它每秒钟会扩展30秒,变成原来的裁剪。如果这没有任何意义,请让我知道,我会尝试解释 是否可以从URL加载图像?如果是,怎么做 图1: 图4: 图5:Java android裁剪图像,扩展为原始裁剪,java,android,image,android-studio,crop,Java,Android,Image,Android Studio,Crop,我想在android上展示一个裁剪过的图像,它每秒钟会扩展30秒,变成原来的裁剪。如果这没有任何意义,请让我知道,我会尝试解释 是否可以从URL加载图像?如果是,怎么做 图1: 图4: 图5: 您可以使用SurfaceView执行此操作 只需在画布上绘制位图的特定部分,并在绘制线程的while循环中每次迭代都将其展开 如果我理解正确,此代码将完成以下工作: import android.content.Context; import android.graphics.Bitmap; impo
您可以使用SurfaceView执行此操作 只需在画布上绘制位图的特定部分,并在绘制线程的while循环中每次迭代都将其展开 如果我理解正确,此代码将完成以下工作:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class ExpandView extends SurfaceView implements SurfaceHolder.Callback {
private DrawThread drawThread;
public ExpandView(Context context) {
super(context);
}
public ExpandView(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.YOUR_DRAWABLE_ID);
drawThread = new DrawThread(holder, bitmap);
drawThread.setRunning(true);
drawThread.start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
drawThread.setRunning(false);
while (retry) {
try {
drawThread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
private class DrawThread extends Thread {
private static final int FRAME_RATE = 30;
private static final float ANIMATION_SPEED_MILLIS = 10_000;
private Bitmap newBitmap;
private int canvasWidth;
private int canvasHeight;
private int bitmapWidth;
private int bitmapHeight;
private boolean isRunning;
private final SurfaceHolder surfaceHolder;
private Bitmap bitmap;
private long startTime;
private long lastDrawTime;
private Paint paint;
//crop rate should be >=0 and <= 1
private float startCropRate = 0.2f;
private float targetCropRate = 1;
private float currentCropRate;
private boolean expand;
private int verticalOffset;
private int horizontalOffset;
private int newWidth;
private int newHeight;
private int newX;
private int newY;
public DrawThread(SurfaceHolder surfaceHolder, Bitmap bitmap) {
this.surfaceHolder = surfaceHolder;
canvasWidth = surfaceHolder.getSurfaceFrame().width();
canvasHeight = surfaceHolder.getSurfaceFrame().height();
this.bitmap = resizeBitmap(bitmap, canvasHeight, canvasWidth);
bitmapWidth = this.bitmap.getWidth();
bitmapHeight = this.bitmap.getHeight();
paint = new Paint(Paint.DITHER_FLAG);
expand = startCropRate > targetCropRate;
}
private Bitmap resizeBitmap(Bitmap bm, int canvasHeight, int canvasWidth) {
int width = bm.getWidth();
int height = bm.getHeight();
float scale = Math.min(canvasWidth/(float)width, canvasHeight/(float)height);
Matrix matrix = new Matrix();
matrix.setScale(scale, scale);
Bitmap resizedBitmap = Bitmap.createBitmap(
bm, 0, 0,width,height, matrix, false);
bm.recycle();
return resizedBitmap;
}
@Override
public void run() {
Canvas canvas;
long currentTime;
long animationTime;
float newScale;
startTime = System.currentTimeMillis();
while (isRunning) {
if (currentCropRate == targetCropRate) {
isRunning = false;
return;
}
currentTime = System.currentTimeMillis();
if (currentTime - lastDrawTime < 1000 / FRAME_RATE) {
continue;
}
animationTime = currentTime - startTime;
newScale = startCropRate + (targetCropRate - startCropRate) * (animationTime / ANIMATION_SPEED_MILLIS);
currentCropRate = expand ? Math.max(targetCropRate, newScale) : Math.min(newScale, targetCropRate);
lastDrawTime = currentTime;
canvas = null;
try {
canvas = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
canvas.drawColor(Color.BLACK, PorterDuff.Mode.CLEAR);
drawImage(canvas);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
private void drawImage(Canvas canvas) {
newWidth = (int) (bitmapWidth * currentCropRate);
newHeight = (int) (bitmapHeight * currentCropRate);
newX = (bitmapWidth - newWidth) / 2;
newY = (bitmapHeight - newHeight) / 2;
newBitmap = Bitmap.createBitmap(bitmap, newX, newY,newWidth,newHeight);
verticalOffset = (canvasHeight - newBitmap.getHeight()) / 2;
horizontalOffset = (canvasWidth - newBitmap.getWidth()) / 2;
canvas.drawBitmap(newBitmap, horizontalOffset, verticalOffset, paint);
}
private void setRunning(boolean running) {
this.isRunning = running;
}
}
}
为我们提供一些代码和一些解释。这是图像视图吗!?这是怎么发生的?我还没有密码。我在想一个图像视图,它显示了一个裁剪过的图像,30秒后图像会扩展回其原始比例,例如像动画一样。我希望这能回答你的问题:)一个例子会更好好的,我会为你做的,等一下我需要完成一些工作。这可能是一个愚蠢的问题,但我如何将此代码定向到特定的图像视图?因此,您可以实时查看进度。此代码是一个随时可用的视图。只需在项目中创建ExpandView.class并将此代码复制到那里。然后将此视图添加到layout.xml。将
R.drawable.YOUR_drawable_ID
替换为res/drawable文件夹中的一些图像资源(在Bitmap Bitmap=BitmapFactory.decodeResource(getResources(),R.drawable.YOUR_drawable_ID);
)并检查其工作方式。这会导致错误:java.lang.RuntimeException:无法实例化活动组件信息{com.(app_name)。(app_name)/com.(app_name)。(app_name).ExpandView}:java.lang.InstantiationException:java.lang.Class没有零参数构造函数
Bitmap bitmap = null;
try{
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.cleaf5, options);
}catch(OutOfMemoryError e)
try{
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.cleaf5, options);
}catch(OutOfMemoryError e) {}
}
if(bitmap != null){
//do smth
}