Cast may be needed

[scuniff]

In file:

omero-insight/src/main/java/org/openmicroscopy/shoola/agents/imviewer/browser/BrowserUI.java

Line 134 in 40566b9

double vx = sizeX/d.width;

Regarding this code:

        int sizeX = rl.width;
	int sizeY = rl.height;
	double vx = sizeX/d.width;
	double vy = sizeY/d.height;
	int x = (int) (vx*region.x);
	int y = (int) (vy*region.y);

As is, the division is being done in integer precision.
If double precision is really wanted then sizeX and sizeY need to be cast to double:

	int sizeX = rl.width;
	int sizeY = rl.height;
	double vx = (double)sizeX/d.width;
	double vy = (double)sizeY/d.height;
	int x = (int) (vx*region.x);
	int y = (int) (vy*region.y);

Example snippet:

       double d;
	
	int a=5;
	int b = 2;

	d = a/b;		
	System.out.println("no cast, d is " + d);
			
	d = (double) a/b;
	System.out.println("with cast, d is " + d);

Output:

no cast, d is 2.0
with cast, d is 2.5

[dominikl]

I don't think this matters. Close?

[scuniff]

Sounds ok to me .

I did though look into the code some and got a basic understanding.
The following example shows what the width of the new rectangle would be with and without double precision.

Referring to lines 130 – 138 and just focusing on the width calculation:

	Dimension d = birdEyeView.getImageSize();
	Rectangle rl = canvas.getBounds();
	int sizeX = rl.width;
	int sizeY = rl.height;
	double vx = sizeX/d.width;
	double vy = sizeY/d.height;
	int x = (int) (vx*region.x);
	int y = (int) (vy*region.y);
	int w = (int) (vx*region.width);

Assume:

Canvas is 500x500
Image is 260x260
Region is 200x200

Then……

sizeX=500 // canvas
d.width = 260 // image

then vx would be:
double vx = sizeX/d.width;

vx = 1.9 // double precsion
vx=1 // int precision

Assume:
region.width=200

then width of new Rectangle would be:
int w = (int) (vx*region.width);

w = 380 // with double precision
w = 200 // with int precision

Is this difference between the 2 precisions ok??

[scuniff]

Sorry, closed this by accident....