在设备 android 中保持方向更改的图像上的绘图路径

Question

I have issue for maintaining drawing (lines with use of finger) on image while device orientation changes.

This image shows the drawing on image with finger

After change the orientation, the draw line misplaced.

I have path object which have this drawing data.

Please help me to resolve this. Thanks in advance.

Answer 1

Now, It is obvious that landscape image's height is less than portrait one. So in this situation image is down scale. So we need to calculate using some equations to get that value which require to scale down the Path to adjust the position of that Path

To resolved this, Let's consider the portrait mode's image has H1 height and landscape mode's image has H2 height.

val scale = H2/H1
val matrix = Matrix()
matrix.setScale(scale, scale)
path.transform(matrix)

This way you will update the all the path objects for landscape mode.

Now when you rotate back to portrait mode, you need to undo scaling by below code.

val scale = 1 / (H2/H1)
val matrix = Matrix()
matrix.setScale(scale, scale)
path.transform(matrix)