ImageBrowserAppearance/ImageBrowserController.m

/*
 Copyright (C) 2018 Apple Inc. All Rights Reserved.
 See LICENSE.txt for this sample’s licensing information
 
 Abstract:
 Main controller class for this application.
 */
 
@import Quartz;   // for IKImageBrowserView
 
#import "ImageBrowserView.h"
#import "ImageBrowserController.h"
#import "ImageBrowserBackgroundLayer.h"
 
// Our data source object for the image browser.
@interface myImageObject : NSObject
 
@property (strong) NSURL *url;
 
@end
 
 
#pragma mark -
 
@implementation myImageObject
 
#pragma mark - IKImageBrowserItem
 
// Required methods of the IKImageBrowserItem protocol.
 
// -------------------------------------------------------------------------
//  imageRepresentationType
//
//  Let the image browser knows we use a URL representation.
// -------------------------------------------------------------------------
- (NSString *)imageRepresentationType
{
    return IKImageBrowserNSURLRepresentationType;
}
 
// -------------------------------------------------------------------------
//  imageRepresentation
//
//  Give our representation to the image browser.
// -------------------------------------------------------------------------
- (id)imageRepresentation
{
    return self.url;
}
 
// -------------------------------------------------------------------------
//  imageUID
//
//  Use the absolute filepath of our URL as identifier.
// -------------------------------------------------------------------------
- (NSString *)imageUID
{
    return self.url.path;
}
 
// -------------------------------------------------------------------------
//  imageTitle
//
//  Use the last path component as the title.
// -------------------------------------------------------------------------
- (NSString *)imageTitle
{
    return self.url.lastPathComponent.stringByDeletingPathExtension;
}
 
// -------------------------------------------------------------------------
//  imageSubtitle
//
//  Use the file extension as the subtitle.
// -------------------------------------------------------------------------
- (NSString *)imageSubtitle
{
    return self.url.pathExtension;
}
 
@end
 
 
#pragma mark -
 
@interface ImageBrowserController ()
 
@property (weak) IBOutlet ImageBrowserView *imageBrowser;
@property (strong) NSMutableArray *images;
@property (strong) NSMutableArray *importedImages;
 
@property (assign) NSDragOperation currentDragOperation;
 
@end
 
 
#pragma mark -
 
@implementation ImageBrowserController
 
// -------------------------------------------------------------------------
//  viewDidLoad
// -------------------------------------------------------------------------
- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // Create two arrays : The first is for the data source representation
    // the second one contains temporary imported images for thread safeness.
    _images = [[NSMutableArray alloc] init];
    _importedImages = [[NSMutableArray alloc] init];
    
    // Allow reordering, animations and set the dragging destination delegate.
    [self.imageBrowser setAllowsReordering:YES];
    [self.imageBrowser setAnimates:YES];
    [self.imageBrowser setDraggingDestinationDelegate:self];
    
    // customize the appearance.
    [self.imageBrowser setCellsStyleMask:IKCellsStyleTitled | IKCellsStyleOutlined];
 
    // Background layer.
    ImageBrowserBackgroundLayer *backgroundLayer = [[ImageBrowserBackgroundLayer alloc] init];
    [self.imageBrowser setBackgroundLayer:backgroundLayer];
    backgroundLayer.owner = self.imageBrowser;
    
    // Change default font.
    //
    // Create a centered paragraph style.
    NSMutableParagraphStyle *paraphStyle = [[NSMutableParagraphStyle alloc] init];
    paraphStyle.lineBreakMode = NSLineBreakByTruncatingMiddle;
    paraphStyle.alignment = NSTextAlignmentCenter;
    
    // Change the title font.
    NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
    attributes[NSFontAttributeName] = [NSFont systemFontOfSize:12]; 
    attributes[NSParagraphStyleAttributeName] = paraphStyle;    
    attributes[NSForegroundColorAttributeName] = [NSColor blackColor];
    [self.imageBrowser setValue:attributes forKey:IKImageBrowserCellsTitleAttributesKey];
    
    // Change the selected title font.
    attributes = [[NSMutableDictionary alloc] init];    
    attributes[NSFontAttributeName] = [NSFont boldSystemFontOfSize:12]; 
    attributes[NSParagraphStyleAttributeName] = paraphStyle;    
    attributes[NSForegroundColorAttributeName] = [NSColor whiteColor];
    [self.imageBrowser setValue:attributes forKey:IKImageBrowserCellsHighlightedTitleAttributesKey];
    
    // Change intercell spacing.
    [self.imageBrowser setIntercellSpacing:NSMakeSize(10, 80)];
    
    // Change selection color.
    [self.imageBrowser setValue:[NSColor colorWithCalibratedRed:1 green:0 blue:0.5 alpha:1.0]
                         forKey:IKImageBrowserSelectionColorKey];
    
    // Set initial zoom value.
    [self.imageBrowser setZoomValue:0.5];
    
    _currentDragOperation = NSDragOperationNone;
}
 
// -------------------------------------------------------------------------
//  updateDatasource
//
//  This is the entry point for reloading image browser data and triggering setNeedsDisplay.
// -------------------------------------------------------------------------
- (void)updateDatasource
{
    // Update the datasource, add recently imported items.
    [self.images addObjectsFromArray:self.importedImages];
    
    // Empty the temporary array.
    [self.importedImages removeAllObjects];
    
    // Reload the image browser, which triggers setNeedsDisplay.
    [self.imageBrowser reloadData];
}
 
 
#pragma mark - Import images from file system
 
// -------------------------------------------------------------------------
//  isImageFile:filePath
//
//  This utility method indicates if the file located at 'filePath' is
//  an image file based on the UTI. It relies on the ImageIO framework for the
//  supported type identifiers.
// -------------------------------------------------------------------------
- (BOOL)isImageFile:(NSString *)filePath
{
    BOOL isImageFile = NO;
    NSError *error = nil;
    NSURL *fileURL = [NSURL fileURLWithPath:filePath];
    
    NSDictionary *resourceValueDict =
        [fileURL resourceValuesForKeys:@[NSURLTypeIdentifierKey] error:&error];
    if (resourceValueDict != nil)
    {
        // Verify that this is a file that the ImageIO framework supports.
        NSString *fileUTI = resourceValueDict[NSURLTypeIdentifierKey];
        if (fileUTI != nil) {
            CFArrayRef supportedTypes = CGImageSourceCopyTypeIdentifiers();
            CFIndex idx, typeCount = CFArrayGetCount(supportedTypes);
            for (idx = 0; idx < typeCount; idx++)
            {
                if (UTTypeConformsTo((__bridge CFStringRef _Nonnull)(fileUTI),
                                     (CFStringRef)CFArrayGetValueAtIndex(supportedTypes, idx)))
                {
                    isImageFile = YES;
                    break;
                }
            }
            CFRelease(supportedTypes);
        }
    }
    return isImageFile;
}
 
// -------------------------------------------------------------------------
//  addImagesWithPathURL:url
// -------------------------------------------------------------------------
- (void)addImagesWithPathURL:(NSURL *)url
{
    BOOL dir = NO;
    [[NSFileManager defaultManager] fileExistsAtPath:url.path isDirectory:&dir];
    if (dir)
    {
        // We are being passed a directory URL, add all the images in that directory.
        NSError *error = nil;
        NSArray *content = [[NSFileManager defaultManager] contentsOfDirectoryAtURL:url
                                                         includingPropertiesForKeys:@[]
                                                                            options:0
                                                                              error:&error];
        if (error == nil)
        {
            for (NSURL *imageURL in content)
            {
                [self addAnImageWithPath:imageURL];
            }
        }
    }
    else
    {
        // We are being passed an image URL, just load the one.
        [self addAnImageWithPath:url];
    }
}
 
// -------------------------------------------------------------------------
//  addAnImageWithPath:url
// -------------------------------------------------------------------------
- (void)addAnImageWithPath:(NSURL *)url
{
    BOOL addObject = NO;
    
    NSDictionary *fileAttribs =
        [[NSFileManager defaultManager] attributesOfItemAtPath:url.path error:nil];
    if (fileAttribs != nil)
    {
        // Check for packages.
        if ([NSFileTypeDirectory isEqualTo:fileAttribs[NSFileType]])
        {
            if ([[NSWorkspace sharedWorkspace] isFilePackageAtPath:url.path] == NO)
            {
                addObject = YES; // If it is a file, it's OK to add.
            }
        }
        else
        {
            addObject = YES; // It is a file, so it's OK to add.
        }
    }
    
    if (addObject && [self isImageFile:url.path])
    {
        // Add a path to the temporary images array.
        myImageObject *p = [[myImageObject alloc] init];
        p.url = url;
        [self.importedImages addObject:p];
    }
}
 
 
#pragma mark - Actions
 
// -------------------------------------------------------------------------
//  addImageButtonClicked:sender
//
//  The user clicked the Add Photos button.
// -------------------------------------------------------------------------
- (IBAction)addImageButtonClicked:(id)sender
{
    NSOpenPanel *openPanel = [NSOpenPanel openPanel];
    openPanel.canChooseDirectories = YES;
    openPanel.allowsMultipleSelection = YES;
    
    void (^openPanelHandler)(NSInteger) = ^(NSInteger returnCode) {
        if (returnCode == NSModalResponseOK)
        {
            // Asynchronously process all URLs from our open panel.
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                for (NSURL *url in openPanel.URLs)
                {
                    [self addImagesWithPathURL:url];
                }
                // Back on the main queue update the data source in the main thread.
                dispatch_async(dispatch_get_main_queue(), ^(void) {
                    [self updateDatasource];
                });
            });
        }
    };
    
    [openPanel beginSheetModalForWindow:self.view.window completionHandler:openPanelHandler];
}
 
// -------------------------------------------------------------------------
//  addImageButtonClicked:sender
//
//  Action called when the zoom slider changes.
// ------------------------------------------------------------------------- 
- (IBAction)zoomSliderDidChange:(id)sender
{
    // Update the zoom value to scale images.
    [self.imageBrowser setZoomValue:[sender floatValue]];
    
    // Redisplay.
    [self.imageBrowser setNeedsDisplay:YES];
}
 
 
#pragma mark - IKImageBrowserDataSource
 
// -------------------------------------------------------------------------
//  numberOfItemsInImageBrowser:view
// ------------------------------------------------------------------------- 
- (NSUInteger)numberOfItemsInImageBrowser:(IKImageBrowserView *)view
{
    // The item count to display is the datadsource item count.
    return self.images.count;
}
 
// -------------------------------------------------------------------------
//  imageBrowser:view:index:
// ------------------------------------------------------------------------- 
- (id)imageBrowser:(IKImageBrowserView *)view itemAtIndex:(NSUInteger)index
{
    return self.images[index];
}
 
 
#pragma mark - IKImageBrowserDataSource
 
// Implement some optional methods of the image browser  datasource protocol to allow
// for removing and reodering items.
 
// -------------------------------------------------------------------------
//  removeItemsAtIndexes:indexes:
//
//  The user wants to delete images, so remove these entries from the data source.  
// ------------------------------------------------------------------------- 
- (void)imageBrowser:(IKImageBrowserView *)view removeItemsAtIndexes:(NSIndexSet *)indexes
{
    [self.images removeObjectsAtIndexes:indexes];
}
 
// -------------------------------------------------------------------------
//  moveItemsAtIndexes:indexes:toIndex
//
//  The user wants to reorder images, update the datadsource and the browser
//  will reflect our changes.
// ------------------------------------------------------------------------- 
- (BOOL)imageBrowser:(IKImageBrowserView *)aBrowser moveItemsAtIndexes:(NSIndexSet *)indexes toIndex:(NSUInteger)destinationIndex
{
    NSMutableArray *temporaryArray = [[NSMutableArray alloc] init];
 
    // First remove items from the data source and keep them in a temporary array.
    for (NSUInteger index = indexes.lastIndex; index != NSNotFound; index = [indexes indexLessThanIndex:index])
    {
        if (index < destinationIndex)
        {
            destinationIndex --;
        }
 
        id obj = self.images[index];
        [temporaryArray addObject:obj];
        [self.images removeObjectAtIndex:index];
    }
 
    // Then insert the removed items at the appropriate location.
    for (NSUInteger index = 0; index < temporaryArray.count; index++)
    {
        [self.images insertObject:temporaryArray[index] atIndex:destinationIndex];
    }
 
    return YES;
}
 
 
#pragma mark - Drag and Drop
 
// -------------------------------------------------------------------------
//  dragOperation:sender
// -------------------------------------------------------------------------
- (NSDragOperation)dragOperation:(id <NSDraggingInfo>)sender
{
    NSDragOperation result = NSDragOperationNone;
    
    NSPasteboard *pboard = [sender draggingPasteboard];
    NSArray *filenames = [pboard propertyListForType:NSFilenamesPboardType];
    
    BOOL dragNotAccepted = NO;
    
    for (NSString *fileName in filenames)
    {
        if (![self isImageFile:fileName])
        {
            dragNotAccepted = YES;
            break;
        }
    }
    
    if (!dragNotAccepted)
    {
        result = NSDragOperationCopy;
    }
    
    return result;
}
 
// -------------------------------------------------------------------------
//  draggingEntered:sender
//
//  Accept dropping of images.
// -------------------------------------------------------------------------
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender
{
    _currentDragOperation = [self dragOperation:sender];
    
    return [self dragOperation:sender];
}
 
// -------------------------------------------------------------------------
//  draggingUpdated:sender
// -------------------------------------------------------------------------
- (NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender
{
    return self.currentDragOperation;
}
 
// -------------------------------------------------------------------------
//  performDragOperation:sender
// ------------------------------------------------------------------------- 
- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
{
    NSData *data = nil;
    NSPasteboard *pasteboard = [sender draggingPasteboard];
 
    // Look for paths on the pasteboard.
    if ([pasteboard.types containsObject:NSFilenamesPboardType])
    {
        data = [pasteboard dataForType:NSFilenamesPboardType];
    }
    
    if (data != nil)
    {
        // Retrieve the paths.
        NSError *error;
        NSArray *filenames =
            [NSPropertyListSerialization propertyListWithData:data
                                                      options:NSPropertyListImmutable
                                                       format:nil
                                                        error:&error];
 
        // Add path URLs to the data source.
        NSMutableArray *urls = [NSMutableArray array];
        for (NSString *file in filenames)
        {
            [urls addObject:[NSURL fileURLWithPath:file]];
        }
        
        for (NSURL *url in urls)
        {
            [self addImagesWithPathURL:url];
        }
        // Make the image browser reload the data source,
        [self updateDatasource];
    }
 
    // We accepted the drag operation,
    return YES;
}
 
@end


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