I'm trying to implement mouse picking using gluUnProject but the vector it returns seems of.
/* create ray */
NSPoint mousePosition = [event locationInWindow];
CGFloat clickX = (mousePosition.x/750-0.5)*2;
CGFloat clickY = (mousePosition.y/750-0.5)*2;
GLint viewport[4];
GLdouble modelview[16];
GLdouble projection[16];
GLdouble nearx, neary, nearz;
GLdouble farx, fary, farz;
glGetIntegerv(GL_VIEWPORT, viewport);
glGetDoublev(GL_MODELVIEW_MATRIX, modelview);
glGetDoublev(GL_PROJECTION_MATRIX, projection);
gluUnProject(clickX, clickY, 0.0f, modelview, projection, viewport, &nearx, &neary, &nearz);
gluUnProject(clickX, clickY, 1.0f, modelview, projection, viewport, &farx, &fary, &farz);
NSLog(#"%f %f %f", farx-nearx, fary-neary, farz-nearz);
output when clicking
2020-08-18 03:00:24.092021+0200 3D[2266:115052] -165.663323 -165.669172 -496.999605
The camera is at position (0,0,5) looking at (0,0,0). The click is done at the middle of the window (clickX=0, clickY=0). I expect the direction to be (0,0,-1). The ray should not deviate in a left/bottom direction. What am I doing wrong ?
Related
I'm trying to warp the mouse using NSWindow local coordinates (but I'm starting from local coordinates in px instead of pt, with the y-axis reversed).
-(void)setProperRelativeMouseLocationTo:(NSPoint)loc
{
CGFloat scale = [[m_window screen] backingScaleFactor];
NSPoint point = NSMakePoint(loc.x / scale, loc.y / scale);
point.y = [m_view frame].size.height - point.y;
NSRect rect = NSZeroRect;
rect.origin = point;
rect = [m_window convertRectToScreen:rect];
point = rect.origin;
const float screenHeight = [[m_window screen] frame].size.height;
point.y = screenHeight - point.y;
warpCursor(point);
}
void warpCursor(NSPoint loc)
{
CGPoint newCursorPosition = CGPointMake(loc.x, loc.y);
CGWarpMouseCursorPosition(newCursorPosition);
}
However, the result is unexpected on one of my screens, the x-axis is correct, but the y-axis is off by 280pt.
This value is not random, it corresponds to the gap between the two screens I'm using : the left is 1280*800 (pt) and the second one is 1920*1080 (pt) (the left one has backing scale factor of 2, while the right one has factor 1).
On the left screen, the mouse is warped exactly where it should be (if I read its local coordinates, they correspond to the ones I asked it to warp to).
Cocoa screen coordinates have their origin at the lower-left of the primary screen. Core Graphics coordinates have their origin at the top-left of the primary screen. Therefore, you have to use the primary screen's height to convert between the two.
You have:
const float screenHeight = [[m_window screen] frame].size.height;
point.y = screenHeight - point.y;
You need:
const float screenHeight = [[NSScreen screens][0] frame].size.height;
point.y = screenHeight - point.y;
I'm trying draw elements of a Speed Gauge using Core Graphics on OSX. I've almost got it but need a little bit of help on the center ticks inside of the gauge. Here is the image of what I'm trying to do:
Here is an image of what I've got so far:
I know how to draw the circle rings and how to draw segments based around the center of the gauge like this:
- (void)drawOuterGaugeRingsInRect:(CGContextRef)contextRef rect:(NSRect)rect {
CGContextSetLineWidth(contextRef,self.gaugeRingWidth);
CGContextSetStrokeColorWithColor(contextRef, [MyColors SpeedGaugeOuterRingGray].CGColor);
CGFloat startRadians = 0;
CGFloat endRadians = M_PI*2;
CGFloat radius = self.bounds.size.width/2 - 5;
CGContextAddArc(contextRef, CGRectGetMidX(rect),CGRectGetMidY(rect),radius,startRadians,endRadians,YES);
//Render the outer gauge
CGContextStrokePath(contextRef);
//Draw the inner gauge ring.
radius -= self.gaugeRingWidth;
CGContextSetStrokeColorWithColor(contextRef, [MyColors SpeedGaugeInnerRingGray].CGColor);
CGContextAddArc(contextRef, CGRectGetMidX(rect),CGRectGetMidY(rect),radius,startRadians,endRadians,YES);
//Render the inner gauge
CGContextStrokePath(contextRef);
radius -= self.gaugeRingWidth;
//Draw and fill the gauge background
CGContextSetFillColorWithColor(contextRef, [MyColors SpeedGaugeCenterFillBlack ].CGColor);
CGContextSetStrokeColorWithColor(contextRef, [MyColors SpeedGaugeCenterFillBlack].CGColor);
CGContextAddArc(contextRef, CGRectGetMidX(rect),CGRectGetMidY(rect),radius,startRadians,endRadians,YES);
//Render and fill the gauge background
CGContextDrawPath(contextRef, kCGPathFillStroke);
/*BLUE CIRCULAR DIAL */
//Prepare to draw the blue circular dial.
radius -= self.gaugeRingWidth/2;
//Adjust gauge ring width
CGContextSetLineWidth(contextRef,self.gaugeRingWidth/2);
CGContextSetStrokeColorWithColor(contextRef, [MyColors SpeedGaugeBlue].CGColor);
CGFloat startingRadians = [MyMathHelper degressToRadians:135];
CGFloat endingRadians = [MyMathHelper degressToRadians:45];
CGContextAddArc(contextRef, CGRectGetMidX(rect),CGRectGetMidY(rect),radius,startingRadians,endingRadians,NO);
//Render the blue gauge line
CGContextStrokePath(contextRef);
}
The code above is called in the drawRect: method in my NSView
The key section is the code here:
- (void)drawInnerDividerLines:(CGContextRef)context rect:(NSRect)rect {
CGFloat centerX = CGRectGetMidX(rect);
CGFloat centerY = CGRectGetMidY(rect);
CGContextSetLineWidth (context, 3.0);
CGContextSetRGBStrokeColor (context, 37.0/255.0, 204.0/255.0, 227.0/255.0, 0.5);
CGFloat destinationX = centerX + (centerY * (cos((135)*(M_PI/180))));
CGFloat destinationY = centerY + (centerX * (sin((135)*(M_PI/180))));
NSPoint destinationPoint = NSMakePoint(destinationX, destinationY);
CGContextMoveToPoint(context, centerX, centerY);
CGContextAddLineToPoint(context, destinationPoint.x, destinationPoint.y);
CGContextStrokePath(context);
}
I understand what is going on here but the problem I'm trying to solve is drawing the little lines, off of the inner blue line that extend toward the center point of the View, but do not draw all the way to the center. I'm a little unsure on how to modify the math and drawing logic to achieve this. Here is the unit circle I based the angles off of for Core Graphics Drawing.
The main problems I'm trying to solve are:
How to define the proper starting point off of the light blue inner line as a staring point for each gauge tick. Right now, I'm drawing the full line from the center to the edge of the gauge.
How to control the length of the tick gauge as it draws pointed toward the center off of it's origin point on the blue line.
Any tips or advice that would point in me in the right direction to solve this would be appreciated.
I recommend using vectors. You can find a line to any point on the circle given an angle by calculating:
dirX = cos(angle);
dirY = sin(angle);
startPt.x = center.x + innerRadius * dirX;
startPt.y = center.y + innerRadius * dirY;
endPt.x = center.x + outerRadius * dirX;
endPt.y = center.y + outerRadius * dirY;
You can then plot a line between startPt and endPt.
Any tips or advice that would point in me in the right direction to solve this would be appreciated.
Given a point on the circumference of your circle at a certain angle around the centre you can form a right angled triangle, the radius is the hypotenuse, and the other two sides being parallel to the x & y axes (ignore for a moment the degenerate case where the point is at 0, 90, 180 or 270 deg). Given that with the sin & cos formula (remember SOHCAHTOA from school) and some basic math you can calculate the coordinates of the point, and using that draw a radius from the centre to the point.
The end points of a "tick" mark just lie on circles of different radii, so the same math will give you the end points and you can draw the tick. You just need to decide the radii of these circles, i.e. the distance along your original radius the end points of the tick should be.
HTH
Another approach to avoid the trigonometry is to rotate the transformation matrix and just draw a vertical or horizontal line.
// A vertical "line" of width "width" along the y axis at x==0.
NSRect tick = NSMakeRect(-width / 2.0, innerRadius, width, outerRadius - innerRadius);
NSAffineTransform* xform = [NSAffineTransform transform];
// Move the x and y axes to the center of your speedometer so rotation happens around it
[xform translateXBy:center.x yBy:center.y];
// Rotate the coordinate system so that straight up is actually at your speedometer's 0
[xform rotateByDegrees:135];
[xform concat];
// Create a new transform to rotate back around for each tick.
xform = [NSAffineTransform transform];
[xform rotateByDegrees:-270.0 / numTicks];
for (int i = 0; i < numTicks; i++)
{
NSRectFill(tick);
[xform concat];
}
You probably want to wrap this in [NSGraphicsContext saveGraphicsState] and [NSGraphicsContext restoreGraphicsState] so the transformation matrix is restored when you're done.
If you want two different kinds of tick marks (major and minor), then have two different rects and select one based on i % 10 == 0 or whatever. Maybe also toggle the color. Etc.
I need to create my own coordinate system in UIView, where 0,0 is center of UIView. But I don't know ho to do this. Please help.
UIView *view = /*...*/;
CGContextRef ctx = /*...*/;
/* Shift center from UL corner to mid-x, mid-y. */
CGRect bounds = [view bounds];
CGFloat hx = bounds.size.width / 2.0;
CGFloat hy = bounds.size.height / 2.0;
CGContextTranslateCTM(ctx, hx, hy);
/* y still increases down, and x to the right. */
/* if you want y to increase up, then flip y: */
CGContextScaleCTM(ctx, 1.0/*sx*/, -1.0/*sy*/);
By default, (0,0) is in the upper left corner of the view. To move this point to the view's center, modify its bounds:
CGFloat width = self.bounds.size.width;
CGFloat height = self.bounds.size.height;
self.bounds = CGRectMake(-width/2.0, -height/2.0, width, height);
Make sure to repeat this calculation whenever the size of the view changes.
I have a "world view," so to speak, that consists of a large, zoomable area on a UIScrollView. I want several buttons to retain their world location when I pinch to zoom, much like pins in Google Maps do. The code I have been trying (I have been coding for hours, but I think it sounds right...although I may be just burned out) is:
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
CGPoint center = button.center;
center.y = center.y * scrollView.zoomScale;
center.x = center.x * scrollView.zoomScale;
button.center = center;
NSLog(#"Button coordinates are %f, %f, zoomScale is %f", button.center.x, button.center.y, scrollView.zoomScale);
}
Can anyone see what I'm doing wrong?
Thanks in advance!
I solved this by setting the CGPoint 'center' only once, on view load, and then calculating a new center point based off of the original location.
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
CGPoint newCenter = center; //center is set at load time, and only once
newCenter.y = center.y * scrollView.zoomScale; //new center is calculated on original position
newCenter.x = center.x * scrollView.zoomScale;
button.center = newCenter;
NSLog(#"Button coordinates are %f, %f, zoomScale is %f", button.center.x, button.center.y, scrollView.zoomScale);
}
Sorry about mistagging the question, Peter.
You don't need to do all the maths yourself. UIScrollView's base class, UIView, has four methods for converting between coordinate systems, which in the case of a UIScrollView take zooming and panning into account:
– convertPoint:toView:
– convertPoint:fromView:
– convertRect:toView:
– convertRect:fromView:
See the UIView documentation at http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
I have a subclass of NSView, and in that I'm drawing an NSImage. I'm unsing NSAffineTransforms to rotate, translate and scale the image.
Most of it works fine. However, sometimes, the transforms just don't seem to get activated.
For example, when I resize the window, the rotate transform doesn't happen.
When I zoom in on the image, it puts the lower left of the image in the correct place, but doesn't zoom it, but it does zoom the part of the image that would be to the right of the original sized image. If I rotate this, it zooms correctly, but translates wrong. (The transation may be a calculation error on my part)
Here is the code of my drawRect: (sorry for the long code chunk)
- (void)drawRect:(NSRect)rect
{
// Drawing code here.
double rotateDeg = -90* rotation;
NSAffineTransform *afTrans = [[NSAffineTransform alloc] init];
NSGraphicsContext *context = [NSGraphicsContext currentContext];
NSSize sz;
NSRect windowFrame = [[self window] frame];
float deltaX, deltaY;
NSSize superSize = [[self superview] frame].size;
float height, width, sHeight, sWidth;
NSRect imageRect;
if(image)
{
sz = [ image size];
imageRect.size = sz;
imageRect.origin = NSZeroPoint;
imageRect.size.width *= zoom;
imageRect.size.height *= zoom;
height = sz.height * zoom ;
width = sz.width *zoom ;
sHeight = superSize.height;
sWidth = superSize.width;
}
I need to grab the sizes of everything early so that I can use them later when I rotate. I am not sure that I need to protect any of that, but I'm paranoid from years of C...
[context saveGraphicsState];
// rotate
[afTrans rotateByDegrees:rotateDeg];
// translate to account for window size;
deltaX = 0;
deltaY = 0;
// translate to account for rotation
// in 1 and 3, X and Y are reversed because the entire FRAME
// (inculding axes) is rotated!
switch (rotation)
{
case 0:
// NSLog(#"No rotation ");
break;
case 1:
deltaY -= (sHeight - height);
deltaX -= sHeight ;
break;
case 2:
deltaX -= width;
deltaY -= ( 2*sHeight - height);
// it's rotating around the lower left of the FRAME, so,
// we need to move it up two frame hights, and then down
// the hieght of the image
break;
case 3:
deltaX += (sHeight - width);
deltaY -= sHeight;
break;
}
Since I'm rotating around the lower left corner, and I want the image to be locked to the upper left corner, I need to move the image around. When I rotate once, the image is in the +- quadrant, so I need to shift it up one view-height, and to the left a view-height minus an image height. etc.
[afTrans translateXBy:deltaX yBy:deltaY];
// for putting image in upper left
// zoom
[afTrans scaleBy: zoom];
printMatrix([afTrans transformStruct]);
NSLog(#"zoom %f", zoom);
[afTrans concat];
if(image)
{
NSRect drawingRect = imageRect;
NSRect frame = imageRect;
frame.size.height = MAX(superSize.height, imageRect.size.height) ;
[self setFrame:frame];
deltaY = superSize.height - imageRect.size.height;
drawingRect.origin.y += deltaY;
This makes the frame the correct size so that the image is in the upper left of the frame.
If the image is bigger than the window, I want the frame to be big enough so scroll bars appear. If it isn't I want the frame to be big enough that it reaches the top of the window.
[image drawInRect:drawingRect
fromRect:imageRect
operation:NSCompositeSourceOver
fraction:1];
if((rotation %2) )
{
float tmp;
tmp = drawingRect.size.width;
drawingRect.size.width = drawingRect.size.height;
drawingRect.size.height = tmp;
}
This code may be entirely historical, now that I look at it... the idea was to swap height andwidth if I rotated 90 or 270 degs.
}
else
NSLog(#"no image");
[afTrans release];
[context restoreGraphicsState];
}
Why do you use the superview's size? That's something you should almost never need to worry about. You should make the view work on its own without dependencies on being embedded in any specific view.
Scaling the size of imageRect is probably not the right way to go. Generally when calling -drawImage you want the source rect to be the bounds of the image, and scale the destination rect to zoom it.
The problems you're reporting kind of sound like you're not redrawing the entire view after changing the transformation. Are you calling -setNeedsDisplay: YES?
How is this view embedded in the window? Is it inside an NSScrollView? Have you made sure the scroll view resizes along with the window?