Add transient document zoom shortcuts

MacDown/Code/Document/MPDocument.m

@@ -182,6 +182,10 @@ - (int)rendererFlags
 @end
 
 
+static const CGFloat MPDocumentZoomMinimum = 0.5;
+static const CGFloat MPDocumentZoomMaximum = 3.0;
+static const CGFloat MPDocumentZoomStep = 1.1;
+
 @interface MPDocument ()
     <NSSplitViewDelegate, NSTextViewDelegate,
 #if __MAC_OS_X_VERSION_MAX_ALLOWED >= 101100
@@ -233,6 +237,7 @@ typedef NS_ENUM(NSUInteger, MPScrollOwner) {
 @property (nonatomic) BOOL needsToUnregister;
 @property (nonatomic) BOOL alreadyRenderingInWeb;
 @property (nonatomic) BOOL renderToWebPending;
+@property (nonatomic) CGFloat documentZoomMultiplier;
 @property (strong) NSArray<NSNumber *> *webViewHeaderLocations;
 @property (strong) NSArray<NSNumber *> *editorHeaderLocations;
 @property (nonatomic) MPScrollOwner scrollOwner;  // Issue #342: Scroll ownership model
@@ -255,6 +260,8 @@ typedef NS_ENUM(NSUInteger, MPScrollOwner) {
 @property (copy) NSString *loadedString;
 
 - (void)scaleWebview;
+- (NSFont *)effectiveEditorBaseFont;
+- (void)applyDocumentZoom;
 - (void)syncScrollers;
 - (void)syncScrollersReverse;
 - (void)updateHeaderLocations;
@@ -437,6 +444,7 @@ - (instancetype)init
         return nil;
 
     self.isPreviewReady = NO;
+    self.documentZoomMultiplier = 1.0;
     _scrollOwner = MPScrollOwnerNeither;
     self.previousSplitRatio = -1.0;
     self.lastNonCollapsedRatio = -1.0;
@@ -899,6 +907,18 @@ - (BOOL)validateUserInterfaceItem:(id<NSValidatedUserInterfaceItem>)item
             return NO;
         }
     }
+    else if (action == @selector(zoomIn:))
+    {
+        return result && self.documentZoomMultiplier < MPDocumentZoomMaximum;
+    }
+    else if (action == @selector(zoomOut:))
+    {
+        return result && self.documentZoomMultiplier > MPDocumentZoomMinimum;
+    }
+    else if (action == @selector(resetZoom:))
+    {
+        return result && fabs(self.documentZoomMultiplier - 1.0) > 0.001;
+    }
     return result;
 }
 
@@ -1995,6 +2015,26 @@ - (IBAction)toggleEditorPane:(id)sender
     [self toggleSplitterCollapsingEditorPane:YES];
 }
 
+- (IBAction)zoomIn:(id)sender
+{
+    self.documentZoomMultiplier =
+        MIN(MPDocumentZoomMaximum, self.documentZoomMultiplier * MPDocumentZoomStep);
+    [self applyDocumentZoom];
+}
+
+- (IBAction)zoomOut:(id)sender
+{
+    self.documentZoomMultiplier =
+        MAX(MPDocumentZoomMinimum, self.documentZoomMultiplier / MPDocumentZoomStep);
+    [self applyDocumentZoom];
+}
+
+- (IBAction)resetZoom:(id)sender
+{
+    self.documentZoomMultiplier = 1.0;
+    [self applyDocumentZoom];
+}
+
 - (IBAction)render:(id)sender
 {
     [self.renderer parseAndRenderLater];
@@ -2165,7 +2205,7 @@ - (void)setupEditor:(NSString *)changedKey
         style.lineSpacing = self.preferences.editorLineSpacing;
 
         // Configure tab stops to match 4-space tab width (fixes #195)
-        NSFont *font = [self.preferences.editorBaseFont copy];
+        NSFont *font = [self effectiveEditorBaseFont];
         if (font)
         {
             NSDictionary *attrs = @{NSFontAttributeName: font};
@@ -2324,17 +2364,38 @@ - (void)redrawDivider
     }
 }
 
+- (NSFont *)effectiveEditorBaseFont
+{
+    NSFont *font = [self.preferences.editorBaseFont copy];
+    if (!font)
+        return nil;
+
+    CGFloat multiplier = self.documentZoomMultiplier > 0.0 ?
+        self.documentZoomMultiplier : 1.0;
+    CGFloat size = MAX(1.0, font.pointSize * multiplier);
+    return [NSFont fontWithDescriptor:font.fontDescriptor size:size] ?: font;
+}
+
+- (void)applyDocumentZoom
+{
+    [self setupEditor:@"editorBaseFontInfo"];
+}
+
 - (void)scaleWebview
 {
-    if (!self.preferences.previewZoomRelativeToBaseFontSize)
-        return;
+    CGFloat multiplier = self.documentZoomMultiplier > 0.0 ?
+        self.documentZoomMultiplier : 1.0;
+    CGFloat scale = multiplier;
 
-    CGFloat fontSize = self.preferences.editorBaseFontSize;
-    if (fontSize <= 0.0)
-        return;
+    if (self.preferences.previewZoomRelativeToBaseFontSize)
+    {
+        CGFloat fontSize = self.preferences.editorBaseFontSize;
+        if (fontSize <= 0.0)
+            return;
 
-    static const CGFloat defaultSize = 14.0;
-    CGFloat scale = fontSize / defaultSize;
+        static const CGFloat defaultSize = 14.0;
+        scale *= fontSize / defaultSize;
+    }
 
 #if 0
     // Sadly, this doesn’t work correctly.

MacDown/Localization/Base.lproj/MainMenu.xib

@@ -368,6 +368,22 @@
                                 </connections>
                             </menuItem>
                             <menuItem isSeparatorItem="YES" id="onf-Mq-Pah"/>
+                            <menuItem title="Zoom In" keyEquivalent="+" id="zNi-uN-Zin">
+                                <connections>
+                                    <action selector="zoomIn:" target="-1" id="ZIn-2S-aCt"/>
+                                </connections>
+                            </menuItem>
+                            <menuItem title="Zoom Out" keyEquivalent="-" id="zNo-uT-Zot">
+                                <connections>
+                                    <action selector="zoomOut:" target="-1" id="ZOt-7q-aCt"/>
+                                </connections>
+                            </menuItem>
+                            <menuItem title="Actual Size" keyEquivalent="0" id="zRs-0m-Act">
+                                <connections>
+                                    <action selector="resetZoom:" target="-1" id="ZRs-0m-aCt"/>
+                                </connections>
+                            </menuItem>
+                            <menuItem isSeparatorItem="YES" id="zSp-zo-001"/>
                             <menuItem title="Left 1:3 Right" id="VW7-VH-9yl">
                                 <modifierMask key="keyEquivalentModifierMask"/>
                                 <connections>
@@ -444,7 +460,8 @@
                                     </binding>
                                 </connections>
                             </menuItem>
-                            <menuItem title="Strikethrough" keyEquivalent="-" id="9CN-Qi-Fln">
+                            <menuItem title="Strikethrough" id="9CN-Qi-Fln">
+                                <modifierMask key="keyEquivalentModifierMask"/>
                                 <connections>
                                     <action selector="toggleStrikethrough:" target="-1" id="rUc-gb-x5q"/>
                                     <binding destination="eq0-c4-vgQ" name="hidden" keyPath="self.preferences.extensionStrikethough" id="kQ0-Wi-BPs">
@@ -509,7 +526,8 @@
                                                 <action selector="convertToH6:" target="-1" id="u4y-F9-JR3"/>
                                             </connections>
                                         </menuItem>
-                                        <menuItem title="Paragraph" keyEquivalent="0" id="xN5-GU-ASF">
+                                        <menuItem title="Paragraph" id="xN5-GU-ASF">
+                                            <modifierMask key="keyEquivalentModifierMask"/>
                                             <connections>
                                                 <action selector="convertToParagraph:" target="-1" id="4BU-GT-Qyv"/>
                                             </connections>

MacDownTests/MPPaneToggleTests.m

@@ -21,6 +21,9 @@ @interface MPDocument (PaneToggleTesting)
 @property CGFloat previousSplitRatio;
 - (IBAction)toggleEditorPane:(id)sender;
 - (IBAction)togglePreviewPane:(id)sender;
+- (IBAction)zoomIn:(id)sender;
+- (IBAction)zoomOut:(id)sender;
+- (IBAction)resetZoom:(id)sender;
 - (void)applyEditorStartInPreviewModePreference;
 @end
 
@@ -81,6 +84,41 @@ - (void)testTogglePreviewPaneIBActionDoesNotCrash
                      @"togglePreviewPane: should not crash");
 }
 
+- (void)testZoomActionsUseTransientDocumentMultiplier
+{
+    NSDictionary *fontInfo = [self.document.preferences.editorBaseFontInfo copy];
+
+    [self.document zoomIn:nil];
+    CGFloat zoomed = [[self.document valueForKey:@"documentZoomMultiplier"] doubleValue];
+
+    XCTAssertGreaterThan(zoomed, 1.0,
+                         @"Zoom in should update the document-local multiplier");
+    XCTAssertEqualObjects(self.document.preferences.editorBaseFontInfo, fontInfo,
+                          @"Zoom should not mutate the saved editor base font preference");
+
+    [self.document resetZoom:nil];
+    CGFloat reset = [[self.document valueForKey:@"documentZoomMultiplier"] doubleValue];
+    XCTAssertEqualWithAccuracy(reset, 1.0, 0.001,
+                               @"Reset zoom should restore actual size");
+}
+
+- (void)testZoomActionsClampAtConfiguredBounds
+{
+    for (NSUInteger i = 0; i < 100; i++)
+        [self.document zoomIn:nil];
+
+    CGFloat zoomedIn = [[self.document valueForKey:@"documentZoomMultiplier"] doubleValue];
+    XCTAssertEqualWithAccuracy(zoomedIn, 3.0, 0.001,
+                               @"Zoom in should clamp at 300 percent");
+
+    for (NSUInteger i = 0; i < 200; i++)
+        [self.document zoomOut:nil];
+
+    CGFloat zoomedOut = [[self.document valueForKey:@"documentZoomMultiplier"] doubleValue];
+    XCTAssertEqualWithAccuracy(zoomedOut, 0.5, 0.001,
+                               @"Zoom out should clamp at 50 percent");
+}
+
 
 #pragma mark - Menu Validation Tests