如何在Android中修复缩放画布的错误坐标 [英] how to fix the wrong coordinates of zoomed canvas in Android
问题描述
我有一个自定义的paint_view,它扩展了image_view,并且与矩阵可缩放。
我为画布设置了此矩阵,并对其进行缩放和拖动,但是在画布缩放或平移之后,路径或可绘制对象被绘制在错误的坐标中。
i尝试设置坐标,但是我不知道它的优化设置方法。
这是我的代码:
I have a custom paint_view that extends image_view and is zoommalble with matrix.
i set this matrix for canvas and scale it and drag it by this matrix, but after canvas scale or translate, paths or drawable objects were drew in wrong coordinates.
i have trid to set the coordinates, but i dont know optimized way to it set.
here is my code:
public class PaintView extends View {
private Path drawPath;
private Paint drawPaint;
private Paint rect_paint;
public boolean zoomMode = false;
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
float oldDist;
PointF start = new PointF();
PointF mid = new PointF();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
public PaintView(Context context) {
super(context);
}
public PaintView(Context context, AttributeSet attrs) {
super(context, attrs);
setupDrawing();
}
public PaintView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
private void setupDrawing() {
drawPath = new Path();
drawPaint = new Paint();
drawPaint.setColor(Color.BLACK);
drawPaint.setAntiAlias(true);
drawPaint.setStyle(Paint.Style.STROKE);
drawPaint.setStrokeJoin(Paint.Join.ROUND);
drawPaint.setStrokeCap(Paint.Cap.ROUND);
drawPaint.setStrokeWidth(10);
rect_paint = new Paint();
rect_paint.setColor(Color.BLACK);
rect_paint.setAntiAlias(true);
rect_paint.setStyle(Paint.Style.STROKE);
rect_paint.setStrokeJoin(Paint.Join.ROUND);
rect_paint.setStrokeCap(Paint.Cap.ROUND);
rect_paint.setStrokeWidth(20);
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.setMatrix(matrix);
canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), rect_paint);
canvas.drawPath(drawPath, drawPaint);
}
public boolean onTouchEvent(MotionEvent event) {
if (zoomMode) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x,
event.getY() - start.y);
}
else if (mode == ZOOM) {
float newDist = spacing(event);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
} 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:
drawPath.lineTo(touchX, touchY);
break;
case MotionEvent.ACTION_UP:
drawPath.lineTo(touchX, touchY);
break;
}
}
invalidate();
return true;
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}}
推荐答案
只需要转换屏幕坐标到修改后的画布坐标:
just need to convert the screen coordinates to the modified canvas coordinates:
//如果我已经移动(转换)了画布,则为:TouchX = TouchX-translatedX; TouchY = TouchY-translationY;
//If i have moved(transleted) the canvas: TouchX = TouchX-translatedX; TouchY=TouchY - translatedY;
//如果我缩放了画布:TouchX = TouchX / scaleFactor; TouchY = TouchY / scaleFactor;
// if i have scale the canvas: TouchX = TouchX/scaleFactor; TouchY = TouchY/scaleFactor;
//如果我已经平移并移动了画布:TouchX =(TouchX-translatedX)/ scaleFactor; TouchY =(TouchY-translatedY)/ scaleFactor;
//if i have translated and moved the canvas: TouchX= (TouchX-translatedX)/scaleFactor; TouchY = (TouchY-translatedY)/scaleFactor;
//然后我们应该使用此TouchX和TouchY进行绘制。
//And then we should draw with this TouchX and TouchY.
这篇关于如何在Android中修复缩放画布的错误坐标的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!