Add zoom controls for the preview pane

MacDown 3000.xcodeproj/project.pbxproj

@@ -107,6 +107,7 @@
 		BA2B9EC2E95175092A97B41E /* MPResourceWatcherSet.m in Sources */ = {isa = PBXBuildFile; fileRef = E6D070A6E080254A17B3B197 /* MPResourceWatcherSet.m */; };
 		CCD97578A2886FFE73BD96F7 /* MPMathJaxRenderingTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 6811F39B13C649FC86C4CE5B /* MPMathJaxRenderingTests.m */; };
 		CHKBOXTGL0001BUILDFILER /* MPCheckboxToggleTests.m in Sources */ = {isa = PBXBuildFile; fileRef = CHKBOXTGL0001FILEREFID /* MPCheckboxToggleTests.m */; };
+		PRVZMTST0001BUILDFILER /* MPPreviewZoomTests.m in Sources */ = {isa = PBXBuildFile; fileRef = PRVZMTST0001FILEREFID /* MPPreviewZoomTests.m */; };
 		D29776CC6E7EB5B4AA2E0537 /* MPFileWatcher.m in Sources */ = {isa = PBXBuildFile; fileRef = A81247E840EB5C07669FF165 /* MPFileWatcher.m */; };
 		D3877A6637DE48017448C8DB /* MPRendererTestHelpers.m in Sources */ = {isa = PBXBuildFile; fileRef = 3E2FC4B9389A012264DC6214 /* MPRendererTestHelpers.m */; };
 		E087CFBB2125A4D2B37C132F /* MPHTMLResourceURLsTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 8552820CEE8D00E83AEE3897 /* MPHTMLResourceURLsTests.m */; };
@@ -547,6 +548,7 @@
 		B3BD139B59E787FBB9F38228 /* MPEditorViewSubstitutionTests.m */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.c.objc; path = MPEditorViewSubstitutionTests.m; sourceTree = "<group>"; };
 		C2B84BF8A8BC4F4B871646F8 /* MPScrollSyncTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MPScrollSyncTests.m; sourceTree = "<group>"; };
 		CHKBOXTGL0001FILEREFID /* MPCheckboxToggleTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MPCheckboxToggleTests.m; sourceTree = "<group>"; };
+		PRVZMTST0001FILEREFID /* MPPreviewZoomTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MPPreviewZoomTests.m; sourceTree = "<group>"; };
 		DDDB87873110C02114439C2C /* MPFileWatcher.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MPFileWatcher.h; sourceTree = "<group>"; };
 		E6D070A6E080254A17B3B197 /* MPResourceWatcherSet.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MPResourceWatcherSet.m; sourceTree = "<group>"; };
 		E70ECDD4241C933C00537A46 /* ru-RU */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "ru-RU"; path = "Localization/ru-RU.lproj/Localizable.strings"; sourceTree = "<group>"; };
@@ -961,6 +963,7 @@
 				197TESTS0F00000000197RSTF /* MPRendererStateTests.m */,
 				C2B84BF8A8BC4F4B871646F8 /* MPScrollSyncTests.m */,
 				CHKBOXTGL0001FILEREFID /* MPCheckboxToggleTests.m */,
+				PRVZMTST0001FILEREFID /* MPPreviewZoomTests.m */,
 				ISSUE285SMARTQTFILEREF /* MPSmartQuoteTests.m */,
 				1FFEB3261972DAB400B2254F /* MPHTMLTabularizeTests.m */,
 				1FFEB32F19ABCD1500B2254F /* MPMarkdownRenderingTests.m */,
@@ -1430,6 +1433,7 @@
 				03224E1B02E36783D5307F4A /* MPDocumentIOTests.m in Sources */,
 				B9A8DE030E3748EB899BD45E /* MPScrollSyncTests.m in Sources */,
 				CHKBOXTGL0001BUILDFILER /* MPCheckboxToggleTests.m in Sources */,
+				PRVZMTST0001BUILDFILER /* MPPreviewZoomTests.m in Sources */,
 				ISSUE285SMARTQTBUILDFILE /* MPSmartQuoteTests.m in Sources */,
 				1F51C9A5194565050015A96F /* MPPreferencesTests.m in Sources */,
 				1FF1420419A8A24800CF8A6A /* MPUtilityTests.m in Sources */,

MacDown/Code/Application/MPToolbarController.m

@@ -7,41 +7,88 @@
 //
 
 #import "MPToolbarController.h"
+#import "MPPreferences.h"
 
 // Because we're creating selectors for methods which aren't in this class
 #pragma GCC diagnostic ignored "-Wundeclared-selector"
 #pragma clang diagnostic ignored "-Wundeclared-selector"
 
 
 static CGFloat itemWidth = 37;
+// Preview-zoom presets must match MPPreviewZoomLevels() in MPDocument.m.
+static NSArray<NSNumber *> *MPToolbarPreviewZoomLevels(void)
+{
+    static NSArray *levels = nil;
+    static dispatch_once_t token;
+    dispatch_once(&token, ^{
+        levels = @[@0.5, @0.75, @0.9, @1.0, @1.1, @1.25, @1.5, @2.0];
+    });
+    return levels;
+}
 
 
 @implementation MPToolbarController
 {
     NSArray *toolbarItems;
     NSArray *toolbarItemIdentifiers;
-    
+
     /**
      * Map toolbar item identifier to it's NSToolbarItem or NSToolbarItemGroup object
      */
     NSMutableDictionary *toolbarItemIdentifierObjectDictionary;
+
+    /**
+     * Weak reference to the zoom popup so we can re-sync its selected item
+     * when the preference changes from elsewhere (menu, keyboard shortcut).
+     */
+    __weak NSPopUpButton *_zoomPopUp;
 }
 
 - (id)init
 {
     self = [super init];
-    
+
     if (!self)
     {
         return nil;
     }
-    
+
     self->toolbarItemIdentifierObjectDictionary = [NSMutableDictionary new];
     [self setupToolbarItems];
-
+
+    // Observe NSUserDefaults so the popup's selection reflects external
+    // changes (View menu actions, ⌘+/⌘-/⌘0). Using KVO on the standard
+    // defaults avoids threading a sync callback through MPDocument.
+    [[NSUserDefaults standardUserDefaults]
+        addObserver:self
+         forKeyPath:@"previewZoomLevel"
+            options:NSKeyValueObservingOptionNew
+            context:NULL];
+
     return self;
 }
 
+- (void)dealloc
+{
+    @try {
+        [[NSUserDefaults standardUserDefaults]
+            removeObserver:self forKeyPath:@"previewZoomLevel"];
+    } @catch (NSException *exception) {
+        // removeObserver may throw if not registered; ignore on teardown.
+    }
+}
+
+- (void)observeValueForKeyPath:(NSString *)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary<NSKeyValueChangeKey,id> *)change
+                       context:(void *)context
+{
+    if ([keyPath isEqualToString:@"previewZoomLevel"])
+    {
+        [self syncPreviewZoomDisplay];
+    }
+}
+
 
 #pragma mark - Private
 
@@ -87,10 +134,14 @@ - (void)setupToolbarItems
             @[
               toggleEditorMenuItem, togglePreviewMenuItem
             ]
-        ]
+        ],
+        [self toolbarItemZoomPopUpWithIdentifier:@"preview-zoom" label:NSLocalizedString(@"Preview Zoom", @"Preview pane zoom toolbar item")]
     ];
-    
+
     self->toolbarItemIdentifiers = [self toolbarItemIdentifiersFromItemsArray:self->toolbarItems];
+
+    // Reflect the persisted preference once everything is wired up.
+    [self syncPreviewZoomDisplay];
 }
 
 /**
@@ -323,13 +374,80 @@ - (NSToolbarItem *)toolbarItemDropDownWithIdentifier:(NSString *)itemIdentifier
         [[popupButton lastItem] setTarget:self.document];
         [[popupButton lastItem] setAction:menuItem.action];
     }
-    
+
     toolbarItem.view = popupButton;
-    
+
     [self->toolbarItemIdentifierObjectDictionary setObject:toolbarItem forKey:itemIdentifier];
-    
+
     return toolbarItem;
 }
 
+/**
+ * Factory method for the preview-zoom popup. Unlike the layout dropdown
+ * this is a regular (non-pull-down) NSPopUpButton: the currently selected
+ * item is shown as the button label so the user sees the active zoom
+ * percentage at a glance. Each menu item is wired to
+ * -selectPreviewZoom: on the document, with the target zoom level
+ * (NSNumber) attached as the item's representedObject.
+ */
+- (NSToolbarItem *)toolbarItemZoomPopUpWithIdentifier:(NSString *)itemIdentifier label:(NSString *)label
+{
+    NSToolbarItem *toolbarItem = [[NSToolbarItem alloc] initWithItemIdentifier:itemIdentifier];
+    toolbarItem.label = label;
+    toolbarItem.paletteLabel = label;
+    toolbarItem.toolTip = label;
+
+    NSPopUpButton *popupButton = [[NSPopUpButton alloc] initWithFrame:NSMakeRect(0, 0, 70, 27) pullsDown:NO];
+    popupButton.bezelStyle = NSBezelStyleTexturedRounded;
+    popupButton.focusRingType = NSFocusRingTypeDefault;
+
+    NSArray<NSNumber *> *levels = MPToolbarPreviewZoomLevels();
+    for (NSNumber *level in levels)
+    {
+        NSString *title = [NSString stringWithFormat:@"%.0f%%", level.doubleValue * 100.0];
+        [popupButton addItemWithTitle:title];
+        NSMenuItem *added = [popupButton lastItem];
+        added.representedObject = level;
+        added.target = self.document;
+        added.action = @selector(selectPreviewZoom:);
+    }
+
+    toolbarItem.view = popupButton;
+
+    [self->toolbarItemIdentifierObjectDictionary setObject:toolbarItem forKey:itemIdentifier];
+    _zoomPopUp = popupButton;
+
+    return toolbarItem;
+}
+
+/**
+ * Update the popup's selection to match the current preview-zoom
+ * preference. If the current preference matches a preset (within
+ * epsilon), that item is selected. Otherwise the popup falls back to
+ * the closest preset so the button always shows a sensible label.
+ */
+- (void)syncPreviewZoomDisplay
+{
+    NSPopUpButton *popup = _zoomPopUp;
+    if (!popup)
+        return;
+
+    CGFloat current = [MPPreferences sharedInstance].previewZoomLevel;
+    NSArray<NSNumber *> *levels = MPToolbarPreviewZoomLevels();
+
+    NSUInteger nearestIdx = 0;
+    CGFloat bestDiff = CGFLOAT_MAX;
+    for (NSUInteger i = 0; i < levels.count; i++)
+    {
+        CGFloat diff = fabs(levels[i].doubleValue - current);
+        if (diff < bestDiff)
+        {
+            bestDiff = diff;
+            nearestIdx = i;
+        }
+    }
+    [popup selectItemAtIndex:(NSInteger)nearestIdx];
+}
+
 
 @end

MacDown/Code/Document/MPDocument.h

@@ -27,4 +27,31 @@
  */
 + (NSString *)toggleCheckboxAtIndex:(NSUInteger)index inMarkdown:(NSString *)markdown;
 
+/**
+ * Step the preview pane zoom level up to the next preset.
+ * Snaps to the next preset > current; beeps if already at the maximum.
+ * Bound to View > Zoom In (Command-+).
+ */
+- (IBAction)zoomPreviewIn:(id)sender;
+
+/**
+ * Step the preview pane zoom level down to the previous preset.
+ * Snaps to the next preset < current; beeps if already at the minimum.
+ * Bound to View > Zoom Out (Command--).
+ */
+- (IBAction)zoomPreviewOut:(id)sender;
+
+/**
+ * Reset the preview pane zoom level to 100%.
+ * Bound to View > Actual Size (Command-0).
+ */
+- (IBAction)actualPreviewSize:(id)sender;
+
+/**
+ * Set the preview pane zoom to the level represented by the sender's
+ * representedObject (NSNumber). Sender may be an NSMenuItem or
+ * NSPopUpButton; the toolbar dropdown uses this entry point.
+ */
+- (IBAction)selectPreviewZoom:(id)sender;
+
 @end