metal animation goes very glitchy

[ddyer0]

This is a different problem than the other "glitchy metal" report. Here a temporary bitmap is being
created and drawn to create an animated rotation. On non-metal platforms this works very smoothly.

Untitled.design.mp4

the top level of the animation does this
Image r2 = rotationImage.rotate(rotateDirectionMath.PI/2animAmount,0x0);
int xp = rotation_center_x-rwidth/2;
int yp = rotation_center_y-rwidth/2;
r2.makeTransparent(0.25).drawImage(gc,xp,yp);

Basically the image is constructed from raw integers and then immediately drawn.
This occurs in the EDT process.

public Image rotate( double angle, int fillColor)
{
int w = getWidth();
int h = getHeight();
int opix[] = new int[wh];
int ipix[] = new int[wh];
getRGB(0,0,w,h,ipix,0,w);
G.Rotate(ipix,opix,w,h,angle,fillColor);
SystemImage.pixelCount += w*h;
Image fin = new Image("temp for rotate");
fin.createImageFromInts(opix,w,h,0,w);

 return(fin);

}
public Image makeTransparent(double percent)
{
int w = getWidth();
int h = getHeight();
int ipix[] = new int[w*h];
getRGB(0,0,w,h,ipix,0,w);

   for(int lim = ipix.length-1; lim>=0; lim--)
   {
	   int pix = ipix[lim];
	   int trans = 0xff&(pix>>24);
       trans = (int)(trans*percent);
	   ipix[lim]=(trans<<24)|(0xffffff&pix);
   }
   Image fin = new Image("temp for transparent image");
   fin.createImageFromInts(ipix,w,h, 0, w);
   return(fin);

}

[ddyer0]

My best guess, studying this video, is createImageFromInts is taking much longer than expected,
and the frame rate can't keep up.

[shai-almog]

We're making several fixes on metal so I think additional issues aren't as helpful until the next update.

However, why don't you use RGBImage and change it in place? You're really thrashing the GC here.

Or just use modifyAlpha if possible which will also add SIMD optimizations.