如何将图像缩放到android中的指定坐标
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【中文标题】如何将图像缩放到android中的指定坐标【英文标题】：how to zoom the image to specified coordinates in android 【发布时间】：2016-04-28 04:37:22 【问题描述】：我想将图像缩放到图像的特定部分（到指定坐标）。 我有一张图片，我在全屏的 android 图像视图中显示它。当我单击一个按钮时，我想将图像缩放到图像的指定坐标。可以说我的坐标是左：500，上：50，宽度：60 和高度：20。我希望将完整图像缩放到指定坐标并将此子图像适合图像视图的中心。
目前我正在通过将图像裁剪到指定坐标来做到这一点。我会得到小图像。我在图像视图中显示它。但我认为这不是一个好的解决方案。
谁能帮我找到实现缩放功能的方法。
【问题讨论】：
可能有帮助：***.com/questions/5602465/… 谢谢 Niko，看来你建议裁剪图像。但我不需要裁剪图像。我只是将图像缩放到给定的坐标。 您找到解决方案了吗？请帮忙 您能找到任何解决方案吗？ 【参考方案1】：为您的图像视图使用此自定义 ImageView 类。然后，如果您想保持捏缩放，那么您也可以使用它，否则从中删除所有手势。您可以在下面给出的类中看到“双击方法”。只需单击按钮即可调用此方法代码。
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace, origRedundantXSpace, origRedundantYSpace;;
float width, height;
static final int CLICK = 3;
static final float SAVE_SCALE = 1f;
float saveScale = SAVE_SCALE;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight, origScale, origBottom,origRight;
ScaleGestureDetector mScaleDetector;
GestureDetector mGestureDetector;
Context context;
public TouchImageView(Context context)
super(context);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener()
@Override
public boolean onTouch(View v, MotionEvent event)
boolean onDoubleTapEvent = mGestureDetector.onTouchEvent(event);
if (onDoubleTapEvent)
// Reset Image to original scale values
mode = NONE;
bottom = origBottom;
right = origRight;
last = new PointF();
start = new PointF();
m = new float[9];
saveScale = SAVE_SCALE;
matrix = new Matrix();
matrix.setScale(origScale, origScale);
matrix.postTranslate(origRedundantXSpace, origRedundantYSpace);
setImageMatrix(matrix);
invalidate();
return true;
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction())
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG)
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width)
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
else if (scaleHeight < height)
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
else
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
);
mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener()
@Override
public boolean onDoubleTapEvent(MotionEvent e)
return true;
);
@Override
public void setImageBitmap(Bitmap bm)
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
public void setMaxZoom(float x)
maxScale = x;
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener
@Override
public boolean onScaleBegin(ScaleGestureDetector detector)
mode = ZOOM;
return true;
@Override
public boolean onScale(ScaleGestureDetector detector)
float mScaleFactor = (float) Math.min(
Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale)
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
else if (saveScale < minScale)
saveScale = minScale;
mScaleFactor = minScale / origScale;
right = width * saveScale - width
- (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width
|| origHeight * saveScale <= height)
matrix.postScale(mScaleFactor, mScaleFactor, width / 2,
height / 2);
if (mScaleFactor < 1)
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1)
if (Math.round(origWidth * saveScale) < width)
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
else
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
else
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1)
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
return true;
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
// Fit to screen.
float scale;
float scaleX = (float) width / (float) bmWidth;
float scaleY = (float) height / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = SAVE_SCALE;
origScale = scale;
// Center the image
redundantYSpace = (float) height - (scale * (float) bmHeight);
redundantXSpace = (float) width - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
origRedundantXSpace = redundantXSpace;
origRedundantYSpace = redundantYSpace;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
origRight = right;
origBottom = bottom;
setImageMatrix(matrix);
希望这会有所帮助！
【讨论】：
你的意思是 if (onDoubleTapEvent) 下的代码？如果是这样，我认为它不会通过获取焦点（TRANS_X，TRANS_Y）和/或图像的宽度和高度（以像素为单位）来计算比例/缩放因子。 您必须在“setScale()”方法中为 sx 和 sy 提供特定值，直到您想要缩放图像。 matrix.setScale(x坐标, y坐标); 感谢您的回复。你的意思是继续设置比例，直到我放大到我想放大的坐标？我也在考虑这一点，但是我们如何找到坐标现在是否在视图范围内并停止缩放？此外，我想缩放的坐标可能在视图内，但我想缩小，以便适合查看和正确可见。请查看问题下添加的赏金评论。【参考方案2】：也许这就是你要找的东西：
/**
* Set zoom to the specified scale. Image will be centered around the point
* (focusX, focusY). These floats range from 0 to 1 and denote the focus point
* as a fraction from the left and top of the view. For example, the top left
* corner of the image would be (0, 0). And the bottom right corner would be (1, 1).
* @param scale
* @param focusX
* @param focusY
* @param scaleType
*/
public void setZoom(float scale, float focusX, float focusY, ScaleType scaleType)
//
// setZoom can be called before the image is on the screen, but at this point,
// image and view sizes have not yet been calculated in onMeasure. Thus, we should
// delay calling setZoom until the view has been measured.
//
if (!onDrawReady)
delayedZoomVariables = new ZoomVariables(scale, focusX, focusY, scaleType);
return;
if (scaleType != mScaleType)
setScaleType(scaleType);
resetZoom();
scaleImage(scale, viewWidth / 2, viewHeight / 2, true);
matrix.getValues(m);
m[Matrix.MTRANS_X] = -((focusX * getImageWidth()) - (viewWidth * 0.5f));
m[Matrix.MTRANS_Y] = -((focusY * getImageHeight()) - (viewHeight * 0.5f));
matrix.setValues(m);
fixTrans();
setImageMatrix(matrix);
更多信息，您可以参考：
This link Github can help you more
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编辑：
请参考这个你会得到你的答案：
The Answer for your question
【讨论】：
是的，我看过这段代码。如果我没记错的话，'scale' 参数决定了缩放级别。但我所需要的只是找到那个缩放（比例）。怎么说？ 根据你的问题，上面的答案是正确的......现在在评论中你正在问一个不同的 eheh 这不对。尝试理解我的评论 - 这种方法将比例（缩放）作为参数，这就是我想在坐标的帮助下计算的。或者，如果您认为我仍然不明白，请尝试多解释一下。我很感激。 我明天试着解释一下我没有笔记本电脑以上是关于如何将图像缩放到android中的指定坐标的主要内容，如果未能解决你的问题，请参考以下文章