我正在开发一个Android着色应用程序，用户可以在其中填充图像位图上的颜色。我想在图像和绘图上实现缩放功能。我所做的是，图像可以完美缩放，但是在其上绘制却无法缩放。
这是我想要的：
下面是我的代码。谢谢
缩放活动代码：
public class PinchZoomPan extends android.support.v7.widget.AppCompatImageView {
//veriable for drawing
public int widthd;
public int heightd;
boolean isEraser=false;
private Path drawPath;
private Paint drawPaint;
private Paint canvasPaint;
private Canvas drawCanvas;
private Bitmap canvasBitmap;
private int paintColor = Color.RED;
//////////////////////////
// veriable for zooming
Matrix matrix = new Matrix();
boolean zoomEnabled = true;
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
int mode = NONE;
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 4f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public PinchZoomPan(Context context) {
super(context);
setupDrawing();
}
public PinchZoomPan(Context context, AttributeSet attr) {
super(context, attr);
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);
setupDrawing();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (zoomEnabled) {
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()) {
//when one finger is touching
//set the mode to DRAG
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
//when two fingers are touching
//set the mode to ZOOM
case MotionEvent.ACTION_POINTER_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = ZOOM;
break;
//when a finger moves
//If mode is applicable move image
case MotionEvent.ACTION_MOVE:
//if the mode is ZOOM or
//if the mode is DRAG and already zoomed
if (mode == ZOOM || (mode == DRAG && saveScale > minScale)) {
float deltaX = curr.x - last.x;// x difference
float deltaY = curr.y - last.y;// y difference
float scaleWidth = Math.round(origWidth * saveScale);// width after applying current scale
float scaleHeight = Math.round(origHeight * saveScale);// height after applying current scale
//if scaleWidth is smaller than the views width
//in other words if the image width fits in the view
//limit left and right movement
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
//if scaleHeight is smaller than the views height
//in other words if the image height fits in the view
//limit up and down movement
else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
}
//if the image doesn't fit in the width or height
//limit both up and down and left and 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);
}
//move the image with the matrix
matrix.postTranslate(deltaX, deltaY);
//set the last touch location to the current
last.set(curr.x, curr.y);
}
break;
//first finger is lifted
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;
// second finger is lifted
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true;
} else {
float touchX = event.getX();
float touchY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
drawPath.moveTo(touchX, touchY);
break;
case MotionEvent.ACTION_MOVE:
if(isEraser) {
drawPath.lineTo(touchX, touchY);
drawCanvas.drawPath(drawPath, drawPaint);
drawPath.reset();
drawPath.moveTo(touchX, touchY);
} else {
drawPath.lineTo(touchX, touchY);
}
break;
case MotionEvent.ACTION_UP:
drawPath.lineTo(touchX, touchY);
drawCanvas.drawPath(drawPath, drawPaint);
drawPath = new Path();
break;
default:
return false;
}
invalidate();
return true;
}
}
public void setZoomEnabled(boolean b) {
this.zoomEnabled = b;
}
@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 = detector.getScaleFactor();
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 = width / bmWidth;
float scaleY = height / bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = height - (scale * bmHeight);
redundantXSpace = width - (scale * bmWidth);
redundantYSpace /= 2;
redundantXSpace /= 2;
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);
setImageMatrix(matrix);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
this.heightd = h;
this.widthd= w;
canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
drawCanvas = new Canvas(canvasBitmap);
}
private void setupDrawing() {
drawPath = new Path();
drawPaint = new Paint();
drawPaint.setColor(paintColor);
drawPaint.setAntiAlias(true);
drawPaint.setDither(true);
drawPaint.setStyle(Paint.Style.STROKE);
drawPaint.setStrokeJoin(Paint.Join.ROUND);
drawPaint.setStrokeCap(Paint.Cap.ROUND);
drawPaint.setStrokeWidth(15);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.save();
super.onDraw(canvas);
canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
canvas.drawPath(drawPath, drawPaint);
invalidate();
}
}
主要活动
public class MainActivity extends AppCompatActivity {
PinchZoomPan pinchZoomPan;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pinchZoomPan = new PinchZoomPan(this);
final Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(10);
pinchZoomPan = findViewById(R.id.drawble_view);
Bitmap bmp = getBitmapFromVectorDrawable(this,R.drawable.ic_launcher_background);
Bitmap alteredBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());
final Canvas canvas = new Canvas(alteredBmp);
canvas.drawBitmap(bmp, 0, 0, paint);
pinchZoomPan.setImageBitmap(alteredBmp);
final Button paintBtn = findViewById(R.id.enable_zoom);
paintBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View button) {
if (paintBtn.getText().toString() =="disable zoom"){
pinchZoomPan.setZoomEnabled(false);
paintBtn.setText("enable zoom");
}
else {
pinchZoomPan.setZoomEnabled(true);
paintBtn.setText("disable zoom");
}
}
});
}
public static Bitmap getBitmapFromVectorDrawable(Context context, int drawableId) {
Drawable drawable = ContextCompat.getDrawable(context, drawableId);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
drawable = (DrawableCompat.wrap(drawable)).mutate();
}
Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}
}