Resize drawing animation from given CGPoints?

I have an iphone version of an App that draws lines on the screen from CGPoints that are stored in a Core Data. all of the drawings are line based without any fill, so basically it draws a line from given point to the next point etc.

Now i am making an iPad version and i want to use the same points (The points were collected with a function I build for tracking the screen and it was a lot of work so I wish to reuse the same points i have).

Does any body has an idea, algorithm or function for drawing the same lines' from the same points but X2 size ?

That 开发者_运维知识库is the draw method:(took it from the GLPaint example of apple)

- (void) playback:(NSNumber*)index 
{

    if (p==0) {
        pointsCount=[[localpoints objectAtIndex:[index intValue]] count]-1;
    }

    isPlayBackOn = YES;

    LetterPoint *point1 = (LetterPoint*)[[localpoints objectAtIndex:[index intValue]] objectAtIndex:p];
    CGPoint p1 = CGPointFromString(point1.float_point);
    LetterPoint *point2 = (LetterPoint*)[[localpoints objectAtIndex:[index intValue]] objectAtIndex:p+1];
    CGPoint p2 = CGPointFromString(point2.float_point);

    [self renderLineFromPoint:p1 toPoint:p2];

    p++;    

    if(p<pointsCount){
        [self performSelector:@selector(playback:) withObject:index afterDelay:0.03];
    }else {
    p=0;
        isPlayBackOn = NO;
    }
}

thanks

shani

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Create an affine transform matrix with a scale factor of 2.0 (and possibly a translation if you want to move the origin of the drawing). Then apply that transform to every point with CGPointApplyAffineTransform() and use the resulting points for drawing.

---

well, just double p1.x and p1.y... transform it just with this:

instead of:

CGPoint p1 = CGPointFromString(point1.float_point);

do this:

CGPoint p1Temp = CGPointFromString(point1.float_point);
CGPoint p1 = CGPointMake(p1Temp.x * 2, p1Temp.y * 2);

and the same for p2...