I am making an image editor (just a simple editor for a program I am making), and I need to find the position of the mouse. Is it possible to do this in Objective-C? If so, how?
EDIT: I just thought I should mention that I have done some research on this and I haven't found anything that works. The code I have in my header file is as follows:
#import <Cocoa/Cocoa.h>
#interface test : NSWindow <NSWindowDelegate> {
}
#end
I can handle any outlets and actions that are needed; I just need to know how to find the position of the mouse.
If you are catching it through an event, such as mouseDown, it will look like this:
- (void)mouseDown:(NSEvent *)theEvent {
NSPoint mouseDownPos = [theEvent locationInWindow];
}
Otherwise, use:
[NSEvent mouseLocation];
EDIT: (Sorry, I wrote NSPoint *, which is wrong, since it's a struct)
Inside a mouse event handler (mouseDown:, mouseUp:, mouseMoved:, etc.), you can ask the event for its locationInWindow. If you need the mouse location at some arbitrary time (generally you won't want to do that, since it's rare for a program to have a one-off need to discover the mouse location), you can do [NSEvent mouseLocation] and it will return the mouse's location at the time in screen coordinates.
If you want the coordinates from the origin of the view itself, use:
NSPoint locationInView = [self convertPoint:[theEvent locationInWindow] fromView:nil];
You can use this NSPoint directly to draw in the NSView coordinates; otherwise with
[theEvent locationInWindow]
you will have the coordinates of the mouse in the window, which is probably not what you want.
Related
I search how to create an application which show the cursor position after click. I find how to reports the current mouse position, but I do not know how show tis in my windows!
I want simply click on a position and show this position on windows label
on Xcode documentation I find - (void)mouseUp:(NSEvent *)theEvent But i dont know how use this!
Subclass your NSWindow and then override the mouseDown Event Method
- (void)mouseDown:(NSEvent *)theEvent
{
//get the point position where the mouse was clicked on the NSWindow !
NSPoint event_location = [theEvent locationInWindow];
NSLog(#"Clicked %f %f",event_location.x,event_location.y);
// use event_location.x and event.location.y to show the position whereever you like
}
Is there anyway to get coordinates for the current position of the keyboard cursor (caret) globally like you can for the mouse cursor position with mouseLocation?
No, there is no way to do it globally.
If you want to do it in your own app, like in an NSTextView, you'd do it like this:
NSRange range = [textView selectedRange];
NSRange newRange = [[textView layoutManager] glyphRangeForCharacterRange:range actualCharacterRange:NULL];
NSRect rect = [[textView layoutManager] boundingRectForGlyphRange:newRange inTextContainer:[textView textContainer]];
rect would be the rect of the selected text, or in the case where there is just an insertion point but no selection, rect.origin is the view-relative location of the insertion point.
The closest you can get would be to use OS X's Accessibility Protocol. This is intended to help disabled users operate the computer, but many applications don't support it, or do not support it very well.
The procedure would be something like:
appRef = AXUIElementCreateApplication(appPID);
focusElemRef = AXUIElementCopyAttributeValue(appRef,kAXFocusedUIElementAttribute, &theValue)
AXUIElementCopyAttributeValue(focusElemRef, kAXSelectedTextRangeAttribute, &selRangeValue);
AXUIElementCopyParameterizedAttributeValue(focusElemRef, kAXBoundsForRangeParameterizedAttribute, adjSelRangeValue, &boundsValue);
Due to the spotty support for the protocol, with many applications you won't get beyond the FocusedUIElementAttribute step, but this does work with some applications.
You can do this easily in macOS 10.0 and up.
For an NSTextView, override the drawInsertionPointInRect:color:turnedOn: method. To translate the caret position relative to the window, use the convertPoint:toView: method. Finally, you can store the translated position in an instance variable.
#interface MyTextView : NSTextView
#end
#implementation MyTextView
{
NSPoint _caretPositionInWindow;
}
- (void)drawInsertionPointInRect:(CGRect)rect color:(NSColor *)color turnedOn:(BOOL)flag
{
[super drawInsertionPointInRect:rect color:color turnedOn:flag];
_caretPositionInWindow = [self convertPoint:rect.origin toView:nil];
}
#end
I have added my NSScrollView over the content view of my NSWindow object. Now I need to know the mouse location over the scrollview.
I have tried the following. But nothing gives the correct location.
- (void)mouseDown:(NSEvent *)theEvent{
NSPoint eventLocation = [theEvent locationInWindow];
NSPoint locationInScroll = [inputScrollView convertPoint:eventLocation toView:nil];
//Both gives the wrong location.
}
The code is correct, assuming that inputScrollView is the document view and the NSScrollView itself.
Another potential problem could be if you change the orientation of the coordinate system in one of the views?
I have a Transparent NSWindow with an simple icon in it that can be dragged around the screen.
My code is:
.h:
#interface CustomView : NSWindow{
}
#property (assign) NSPoint initialLocation;
.m
#synthesize initialLocation;
- (id) initWithContentRect: (NSRect) contentRect
styleMask: (NSUInteger) aStyle
backing: (NSBackingStoreType) bufferingType
defer: (BOOL) flag{
if (![super initWithContentRect: contentRect
styleMask: NSBorderlessWindowMask
backing: bufferingType
defer: flag]) return nil;
[self setBackgroundColor: [NSColor clearColor]];
[self setOpaque:NO];
[NSApp activateIgnoringOtherApps:YES];
return self;
}
- (void)mouseDragged:(NSEvent *)theEvent {
NSRect screenVisibleFrame = [[NSScreen mainScreen] visibleFrame];
NSRect windowFrame = [self frame];
NSPoint newOrigin = windowFrame.origin;
// Get the mouse location in window coordinates.
NSPoint currentLocation = [theEvent locationInWindow];
// Update the origin with the difference between the new mouse location and the old mouse location.
newOrigin.x += (currentLocation.x - initialLocation.x);
newOrigin.y += (currentLocation.y - initialLocation.y);
// Don't let window get dragged up under the menu bar
if ((newOrigin.y + windowFrame.size.height) > (screenVisibleFrame.origin.y + screenVisibleFrame.size.height)) {
newOrigin.y = screenVisibleFrame.origin.y + (screenVisibleFrame.size.height - windowFrame.size.height);
}
// Move the window to the new location
[self setFrameOrigin:newOrigin];
}
- (void)mouseDown:(NSEvent *)theEvent {
// Get the mouse location in window coordinates.
self.initialLocation = [theEvent locationInWindow];
}
I want to display a NSPopover when the users clicks the image of the transparent window. But, as you can see in the code, the mouseDown event is used to get the mouse location (the code above was taken from an example).
What can i do to know when the user clicks the icon just to drag it around or simply clicked it to display the NSPopover?
Thank you
This is the classic situation of receiving the defining event after you need it in order to begin the action. Specifically, you can't know if the mouseDown is the beginning of a drag until after the drag starts. However, you want to act upon that mouseDown if a drag doesn't start.
In iOS (I realize that's not directly relevant to the code here, but it is instructional), there's an entire API built around letting iOS attempt to make these kinds of decisions for you. The entire Gesture system is based on the idea that the user starts to do something that might be one of many different actions, and thus needs to be resolved over time, possibly resulting in cancelled actions during the tracking period.
On OS X, we don't have many systems to help out with this, so if you have something that needs to handle a click and a drag differentially, you will need to defer your next action until a guard time has passed, and if that passes, you can perform the original action. In this case, you will likely want to do the following:
In the mouseDown, begin an NSTimer set for an appropriate guard time (not so long that people will accidentally move the pointer, and not so short that you'll trigger before the user drags) in order to call you back later to trigger the popover.
In the mouseDragged, use a guard area to make sure that if the user just twitches a little, it doesn't count as a drag. This can be irritating, as it sometimes results in needing to drag something farther than it seems necessary in order to begin a drag, so you'll want to either find a magic constant somewhere, or do some experimentation. When the guard area is exceeded, then begin your legitimate drag operation by canceling the NSTimer with [timer invalidate] and do your drag.
In the callback for the timer, display your popover. If the user dragged, the NSTimer will have been invalidated, causing it not to fire, and so the popover won't be displayed.
I have an NSView which I am adding as a sub-view of another NSView. I want to be able to drag the first NSView around the parent view. I have some code that is partially working but there's an issue with the NSView moving in the opposite direction on the Y axis from my mouse drag. (i.e. I drag down, it goes up and the inverse of that).
Here's my code:
// -------------------- MOUSE EVENTS ------------------- \\
- (BOOL) acceptsFirstMouse:(NSEvent *)e {
return YES;
}
- (void)mouseDown:(NSEvent *) e {
//get the mouse point
lastDragLocation = [e locationInWindow];
}
- (void)mouseDragged:(NSEvent *)theEvent {
NSPoint newDragLocation = [theEvent locationInWindow];
NSPoint thisOrigin = [self frame].origin;
thisOrigin.x += (-lastDragLocation.x + newDragLocation.x);
thisOrigin.y += (-lastDragLocation.y + newDragLocation.y);
[self setFrameOrigin:thisOrigin];
lastDragLocation = newDragLocation;
}
The view is flipped, though I changed that back to the default and it didn't seem to make a difference. What am I doing wrong?
The best way to approach this problem is by starting with a solid understanding of coordinate spaces.
First, it is critical to understand that when we talk about the "frame" of a window, it is in the coordinate space of the superview. This means that adjusting the flippedness of the view itself won't actually make a difference, because we haven't been changing anything inside the view itself.
But your intuition that the flippedness is important here is correct.
By default your code, as typed, seems like it would work; perhaps your superview has been flipped (or not flipped), and it is in a different coordinate space than you expect.
Rather than just flipping and unflipping views at random, it is best to convert the points you're dealing with into a known coordinate space.
I've edited your above code to always convert into the superview's coordinate space, because we're working with the frame origin. This will work if your draggable view is placed in a flipped, or non-flipped superview.
// -------------------- MOUSE EVENTS ------------------- \\
- (BOOL) acceptsFirstMouse:(NSEvent *)e {
return YES;
}
- (void)mouseDown:(NSEvent *) e {
// Convert to superview's coordinate space
self.lastDragLocation = [[self superview] convertPoint:[e locationInWindow] fromView:nil];
}
- (void)mouseDragged:(NSEvent *)theEvent {
// We're working only in the superview's coordinate space, so we always convert.
NSPoint newDragLocation = [[self superview] convertPoint:[theEvent locationInWindow] fromView:nil];
NSPoint thisOrigin = [self frame].origin;
thisOrigin.x += (-self.lastDragLocation.x + newDragLocation.x);
thisOrigin.y += (-self.lastDragLocation.y + newDragLocation.y);
[self setFrameOrigin:thisOrigin];
self.lastDragLocation = newDragLocation;
}
Additionally, I'd recommend refactoring your code to simply deal with the original mouse-down location, and the current location of the pointer, rather than deal with the deltas between mouseDragged events. This could lead to unexpected results down the line.
Instead simply store the offset between the origin of dragged view and the mouse pointer (where the mouse pointer is within the view), and set the frame origin to the location of the mouse pointer, minus the offset.
Here is some additional reading:
Cocoa Drawing Guide
Cocoa Event Handling Guide
I think you should calculate according to the position of mouse, cause according to my test,it gets more smooth.Because The way like below only provide the position inside the application's window coordinate system:
[[self superview] convertPoint:[theEvent locationInWindow] fromView:nil];
What I am suggesting is something like this:
lastDrag = [NSEvent mouseLocation];
other codes are just the same.