放大和缩小的 Imageview 问题，以最大和最小级别拖动 [英] Imageview issue with zoom in and out,drag with maximum and minimum levels
问题描述
我已经实现了具有缩放和拖动功能的图像视图.我正在使用矩阵进行缩放和拖动功能.但我的问题是我无法设置最小和最大缩放级别以及拖动空间限制.可以在任何请告诉我如何做到这一点.
I had implemented an image view with the zoom and drag functionalities.I am using matrix for the zoom and drag functionality.But my problem is that I cant set my minimum and maximum zoom level and the drag space limit.can any on e tell me how I can do that.
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);
}
private float spacing(PointF start,PointF end)
{
float x = end.x- start.x;
float y = end.y -start.y;
return FloatMath.sqrt(x * x + y * y);
}
@Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG" );
mode = DRAG;
break;
case MotionEvent.ACTION_UP:
if(mode==DRAG)
{
PointF end=new PointF();
end.set(event.getX(), event.getY());
Log.d("Fling", "Inside the Action Key UP"+spacing(start, end));
float []x = new float[9],org=new float[9];
matrix.getValues(x);
orgMatrix.getValues(org);
Log.d("Fling", "matrixValue"+matrix);
Log.d("Fling", "OrgmatrixValue"+orgMatrix);
float matrixSizex=x[Matrix.MSCALE_X];
float matrixSizey=x[Matrix.MSCALE_Y];
float matrixOrgSizex=org[Matrix.MSCALE_X];
float matrixOrgSizey=org[Matrix.MSCALE_Y];
if(Math.abs(matrixOrgSizex-matrixSizex)<0.17f&&Math.abs(matrixOrgSizey-matrixSizey)<0.17f)
{
Log.d("Fling", "Current Size is equal");
if(spacing(start, end)>30.f)
{
if((start.x>end.x+30)&&(Math.abs(start.y-end.y)<50.0f))
{
Log.d("Fling", "Is From Right To left");
loadedimage.setImageMatrix(orgMatrix);
leftSwipe();
view.setScaleType(ImageView.ScaleType.FIT_XY);
}
else if((end.x>start.x+30)&&(Math.abs(end.y-start.y)<50.0f))
{
Log.d("Fling", "Is From Left To Right");
loadedimage.setImageMatrix(orgMatrix);
rightSwipe();
view.setScaleType(ImageView.ScaleType.FIT_XY);
}
}
}
}
case MotionEvent.ACTION_POINTER_UP: //second finger lifted
mode = NONE;
Log.d(TAG, "mode=NONE" );
break;
case MotionEvent.ACTION_POINTER_DOWN: //second finger down
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 5f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM" );
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
//movement of first finger
PointF end=new PointF();
end.set(event.getX(), event.getY());
Log.d("Fling", "Inside the Action Key UP"+spacing(start, end));
float []x = new float[9],org=new float[9];
matrix.getValues(x);
orgMatrix.getValues(org);
Log.d("Fling", "matrixValue"+matrix);
Log.d("Fling", "OrgmatrixValue"+orgMatrix);
float matrixSizex=x[Matrix.MSCALE_X];
float matrixSizey=x[Matrix.MSCALE_Y];
float matrixOrgSizex=org[Matrix.MSCALE_X];
float matrixOrgSizey=org[Matrix.MSCALE_Y];
if(Math.abs(matrixOrgSizex-matrixSizex)>=0.17f&&Math.abs(matrixOrgSizey-matrixSizey)>=0.17f)
{
matrix.set(savedMatrix);
if (view.getLeft() >= 0)
{
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
}
}
}
else if (mode == ZOOM) { //pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 5f) {
matrix.set(savedMatrix);
scale = newDist / oldDist; //thinking i need to play around with this value to limit it**
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
// Perform the transformation
view.setImageMatrix(matrix);
return true; // indicate event was handled
}
我的示例代码在这里，任何人都可以帮助我设置最小和最大缩放和拖动级别.我也有问题，当我在图像视图中触摸它时，它会在转换为矩阵时自动缩放，我无法让它保持适合设备屏幕.我完全卡在这里........
My Sample code is here can any one help me in setting minimum and maximum zoom and drag level.I also have problem when I touch in the image view it automatically get zoomed when converted to the matrix I cant make it stay fit in the device screen.I am totally stuck here........
推荐答案
为了限制缩放，我将缩放后的矩阵与单位矩阵进行比较，如果它小于单位矩阵，则不将其分配给我的 ImageView，在这种情况下，我将缩放矩阵重置回单位矩阵.我在 Android 上使用 Mono，但我想它在 Java 中几乎是一样的:
To restrict zooming I compare the zoomed matrix with the identity matrix and don't assign it to my ImageView if it's smaller than the identity matrix, in which case I reset the scaled matrix back to the identity matrix. I'm using Mono for Android but I guess it will be almost the same in Java:
//check that zoom is not too small
if (Utils.SmallerThanIdentity(matrix))
{
ResetView(v);
}
实现 SmallerThanIdentity 的地方:
Where SmallerThanIdentity is implemented:
public static bool SmallerThanIdentity(Android.Graphics.Matrix m)
{
float[] values = new float[9];
m.GetValues(values);
return ((values[0] < 1.0) || (values[4] < 1.0) || (values[8] < 1.0));
}
这里是 ResetView.我有 Java 代码:
And here's ResetView. I have Java code for that:
public void resetView(View v)
{
ImageView view = (ImageView)v;
matrix = new Matrix();
view.setScaleType(ImageView.ScaleType.MATRIX);
view.setImageMatrix(matrix);
}
关于滚动，我在将矩阵转换到我想要限制滚动的区域之前使用下面的 ShouldScroll 方法.
Regarding scroll, I use the ShouldScroll method below before translating the matrix to the area where I want to restrict the scrolling.
private bool ShouldScroll(Android.Graphics.Matrix matrix)
{
float[] values = new float[9];
matrix.GetValues(values);
float[] oldValues = new float[9];
oldMatrix.GetValues(oldValues);
float zoomPercentX = values[0] / oldValues[0];
float zoomPercentY = values[4] / oldValues[4];
float tmpW = -(this.Drawable.IntrinsicWidth / 2) * zoomPercentX;
float tmpH = -(this.Drawable.IntrinsicHeight / 2) * zoomPercentY;
return (values[2] < 0.0f) && (values[2] > tmpW) && //horizontal coordinates
(values[5] < 0.0f) && (values[5] > tmpH); //vertical coordinates
}
这篇关于放大和缩小的 Imageview 问题，以最大和最小级别拖动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！
