nsMacCursor.mm

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsMacCursor.h"
#include "nsObjCExceptions.h"
#include "nsDebug.h"
#include "nsDirectoryServiceDefs.h"
#include "nsCOMPtr.h"
#include "nsIFile.h"
#include "nsString.h"

/*! @category   nsMacCursor (PrivateMethods)
    @abstract   Private methods internal to the nsMacCursor class.
    @discussion <code>nsMacCursor</code> is effectively an abstract class. It does not define
   complete behaviour in and of itself, the subclasses defined in this file provide the useful
   implementations.
*/
@interface nsMacCursor (PrivateMethods)

/*! @method     getNextCursorFrame
    @abstract   get the index of the next cursor frame to display.
    @discussion Increments and returns the frame counter of an animated cursor.
    @result     The index of the next frame to display in the cursor animation
*/
- (int)getNextCursorFrame;

/*! @method     numFrames
    @abstract   Query the number of frames in this cursor's animation.
    @discussion Returns the number of frames in this cursor's animation. Static cursors return 1.
*/
- (int)numFrames;

/*! @method     createTimer
    @abstract   Create a Timer to use to animate the cursor.
    @discussion Creates an instance of <code>NSTimer</code> which is used to drive the cursor
   animation. This method should only be called for cursors that are animated.
*/
- (void)createTimer;

/*! @method     destroyTimer
    @abstract   Destroy any timer instance associated with this cursor.
    @discussion Invalidates and releases any <code>NSTimer</code> instance associated with this
   cursor.
 */
- (void)destroyTimer;
/*! @method     destroyTimer
    @abstract   Destroy any timer instance associated with this cursor.
    @discussion Invalidates and releases any <code>NSTimer</code> instance associated with this
   cursor.
*/

/*! @method     advanceAnimatedCursor:
    @abstract   Method called by animation timer to perform animation.
    @discussion Called by an animated cursor's associated timer to advance the animation to the next
   frame. Determines which frame should occur next and sets the cursor to that frame.
    @param      aTimer the timer causing the animation
*/
- (void)advanceAnimatedCursor:(NSTimer*)aTimer;

/*! @method     setFrame:
    @abstract   Sets the current cursor, using an index to determine which frame in the animation to
   display.
    @discussion Sets the current cursor. The frame index determines which frame is shown if the
   cursor is animated. Frames and numbered from <code>0</code> to <code>-[nsMacCursor numFrames] -
   1</code>. A static cursor has a single frame, numbered 0.
    @param      aFrameIndex the index indicating which frame from the animation to display
*/
- (void)setFrame:(int)aFrameIndex;

@end

/*! @class      nsCocoaCursor
    @abstract   Implementation of <code>nsMacCursor</code> that uses Cocoa <code>NSCursor</code>
   instances.
    @discussion Displays a static or animated cursor, using Cocoa <code>NSCursor</code> instances.
   These can be either built-in <code>NSCursor</code> instances, or custom <code>NSCursor</code>s
   created from images. When more than one <code>NSCursor</code> is provided, the cursor will use
   these as animation frames.
*/
@interface nsCocoaCursor : nsMacCursor {
 @private
  NSArray* mFrames;
  NSCursor* mLastSetCocoaCursor;
}

/*! @method     initWithFrames:
    @abstract   Create an animated cursor by specifying the frames to use for the animation.
    @discussion Creates a cursor that will animate by cycling through the given frames. Each element
   of the array must be an instance of <code>NSCursor</code>
    @param      aCursorFrames an array of <code>NSCursor</code>, representing the frames of an
   animated cursor, in the order they should be played.
    @param      aType the corresponding <code>nsCursor</code> constant
    @result     an instance of <code>nsCocoaCursor</code> that will animate the given cursor frames
 */
- (id)initWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType;

/*! @method     initWithCursor:
    @abstract   Create a cursor by specifying a Cocoa <code>NSCursor</code>.
    @discussion Creates a cursor representing the given Cocoa built-in cursor.
    @param      aCursor the <code>NSCursor</code> to use
    @param      aType the corresponding <code>nsCursor</code> constant
    @result     an instance of <code>nsCocoaCursor</code> representing the given
   <code>NSCursor</code>
*/
- (id)initWithCursor:(NSCursor*)aCursor type:(nsCursor)aType;

/*! @method     initWithImageNamed:hotSpot:
    @abstract   Create a cursor by specifying the name of an image resource to use for the cursor
   and a hotspot.
    @discussion Creates a cursor by loading the named image using the <code>+[NSImage
   imageNamed:]</code> method. <p>The image must be compatible with any restrictions laid down by
   <code>NSCursor</code>. These vary by operating system version.</p> <p>The hotspot precisely
   determines the point where the user clicks when using the cursor.</p>
    @param      aCursor the name of the image to use for the cursor
    @param      aPoint the point within the cursor to use as the hotspot
    @param      aType the corresponding <code>nsCursor</code> constant
    @result     an instance of <code>nsCocoaCursor</code> that uses the given image and hotspot
*/
- (id)initWithImageNamed:(NSString*)aCursorImage hotSpot:(NSPoint)aPoint type:(nsCursor)aType;

@end

@implementation nsMacCursor

+ (nsMacCursor*)cursorWithCursor:(NSCursor*)aCursor type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [[[nsCocoaCursor alloc] initWithCursor:aCursor type:aType] autorelease];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

+ (nsMacCursor*)cursorWithImageNamed:(NSString*)aCursorImage
                             hotSpot:(NSPoint)aPoint
                                type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [[[nsCocoaCursor alloc] initWithImageNamed:aCursorImage hotSpot:aPoint
                                               type:aType] autorelease];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

+ (nsMacCursor*)cursorWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [[[nsCocoaCursor alloc] initWithFrames:aCursorFrames type:aType] autorelease];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

+ (NSCursor*)cocoaCursorWithImageNamed:(NSString*)imageName hotSpot:(NSPoint)aPoint {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  nsCOMPtr<nsIFile> resDir;
  nsAutoCString resPath;
  NSString *pathToImage, *pathToHiDpiImage;
  NSImage *cursorImage, *hiDpiCursorImage;

  nsresult rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(resDir));
  if (NS_FAILED(rv)) goto INIT_FAILURE;
  resDir->AppendNative("res"_ns);
  resDir->AppendNative("cursors"_ns);

  rv = resDir->GetNativePath(resPath);
  if (NS_FAILED(rv)) goto INIT_FAILURE;

  pathToImage = [NSString stringWithUTF8String:(const char*)resPath.get()];
  if (!pathToImage) goto INIT_FAILURE;
  pathToImage = [pathToImage stringByAppendingPathComponent:imageName];
  pathToHiDpiImage = [pathToImage stringByAppendingString:@"@2x"];
  // Add same extension to both image paths.
  pathToImage = [pathToImage stringByAppendingPathExtension:@"png"];
  pathToHiDpiImage = [pathToHiDpiImage stringByAppendingPathExtension:@"png"];

  cursorImage = [[[NSImage alloc] initWithContentsOfFile:pathToImage] autorelease];
  if (!cursorImage) goto INIT_FAILURE;

  // Note 1: There are a few different ways to get a hidpi image via
  // initWithContentsOfFile. We let the OS handle this here: when the
  // file basename ends in "@2x", it will be displayed at native resolution
  // instead of being pixel-doubled. See bug 784909 comment 7 for alternates ways.
  //
  // Note 2: The OS is picky, and will ignore the hidpi representation
  // unless it is exactly twice the size of the lowdpi image.
  hiDpiCursorImage = [[[NSImage alloc] initWithContentsOfFile:pathToHiDpiImage] autorelease];
  if (hiDpiCursorImage) {
    NSImageRep* imageRep = [[hiDpiCursorImage representations] objectAtIndex:0];
    [cursorImage addRepresentation:imageRep];
  }
  return [[[NSCursor alloc] initWithImage:cursorImage hotSpot:aPoint] autorelease];

INIT_FAILURE:
  NS_WARNING("Problem getting path to cursor image file!");
  [self release];
  return nil;

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

- (BOOL)isSet {
  // implemented by subclasses
  return NO;
}

- (void)set {
  if ([self isAnimated]) {
    [self createTimer];
  }
  // if the cursor isn't animated or the timer creation fails for any reason...
  if (!mTimer) {
    [self setFrame:0];
  }
}

- (void)unset {
  [self destroyTimer];
}

- (BOOL)isAnimated {
  return [self numFrames] > 1;
}

- (int)numFrames {
  // subclasses need to override this to support animation
  return 1;
}

- (int)getNextCursorFrame {
  mFrameCounter = (mFrameCounter + 1) % [self numFrames];
  return mFrameCounter;
}

- (void)createTimer {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  if (!mTimer) {
    mTimer = [[NSTimer scheduledTimerWithTimeInterval:0.25
                                               target:self
                                             selector:@selector(advanceAnimatedCursor:)
                                             userInfo:nil
                                              repeats:YES] retain];
  }

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

- (void)destroyTimer {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  if (mTimer) {
    [mTimer invalidate];
    [mTimer release];
    mTimer = nil;
  }

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

- (void)advanceAnimatedCursor:(NSTimer*)aTimer {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  if ([aTimer isValid]) {
    [self setFrame:[self getNextCursorFrame]];
  }

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

- (void)setFrame:(int)aFrameIndex {
  // subclasses need to do something useful here
}

- (nsCursor)type {
  return mType;
}

- (void)dealloc {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  [self destroyTimer];
  [super dealloc];

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

@end

@implementation nsCocoaCursor

- (id)initWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  self = [super init];
  NSEnumerator* it = [aCursorFrames objectEnumerator];
  NSObject* frame = nil;
  while ((frame = [it nextObject])) {
    NS_ASSERTION([frame isKindOfClass:[NSCursor class]],
                 "Invalid argument: All frames must be of type NSCursor");
  }
  mFrames = [aCursorFrames retain];
  mFrameCounter = 0;
  mType = aType;
  return self;

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

- (id)initWithCursor:(NSCursor*)aCursor type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  NSArray* frame = [NSArray arrayWithObjects:aCursor, nil];
  return [self initWithFrames:frame type:aType];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

- (id)initWithImageNamed:(NSString*)aCursorImage hotSpot:(NSPoint)aPoint type:(nsCursor)aType {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [self initWithCursor:[nsMacCursor cocoaCursorWithImageNamed:aCursorImage hotSpot:aPoint]
                         type:aType];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

- (BOOL)isSet {
  return [NSCursor currentCursor] == mLastSetCocoaCursor;
}

- (void)setFrame:(int)aFrameIndex {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  NSCursor* newCursor = [mFrames objectAtIndex:aFrameIndex];
  [newCursor set];
  mLastSetCocoaCursor = newCursor;

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

- (int)numFrames {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [mFrames count];

  NS_OBJC_END_TRY_BLOCK_RETURN(0);
}

- (NSString*)description {
  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;

  return [mFrames description];

  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
}

- (void)dealloc {
  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;

  [mFrames release];
  [super dealloc];

  NS_OBJC_END_TRY_IGNORE_BLOCK;
}

@end