Prevent translation out of pinch-zoom about pinch-zoom

[jordan-webdev]

I ran into this issue, too.

[dupuisv]

Same

[WernerRaath]

Same here

[dupuisv]

To avoid the image moved outside the viewing windows , something like this do the job

// Correct for x
		/*
        if (topLeft.x > thisBounds.width) {
            x += thisBounds.width - topLeft.x;
        }
        else if (bottomRight.x < 0) {
            x += -bottomRight.x;
        }
		*/
		if (bottomRight.x < thisBounds.width*0.8) {
			x += thisBounds.width*0.8 - bottomRight.x;
		} else if (topLeft.x > thisBounds.width*0.2) {
			x = thisBounds.width*0.2;
		}
        // Correct for y
		/*
        if (topLeft.y > thisBounds.height) {
            y += thisBounds.height - topLeft.y;
        }
        else if (bottomRight.y < 0) {
            y += -bottomRight.y;
        }
		*/
		if (bottomRight.y < thisBounds.height*0.8) {
			y += thisBounds.height*0.8 - bottomRight.y;
		} else if (topLeft.y > thisBounds.height*0.2) {
			y = thisBounds.height*0.2;
		}