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Annotation of Examples/AppKit/Draw/graphicsUndo.subproj/GridChange.m, revision 1.1

1.1     ! root        1: #import "drawundo.h"
        !             2: 
        !             3: @interface GridChange(PrivateMethods)
        !             4: 
        !             5: @end
        !             6: 
        !             7: @implementation GridChange
        !             8: 
        !             9: - initGraphicView:aGraphicView
        !            10: {
        !            11:     [super init];
        !            12:     graphicView = aGraphicView;
        !            13: 
        !            14:     return self;
        !            15: }
        !            16: 
        !            17: - (const char *)changeName
        !            18: {
        !            19:     return NXLocalStringFromTable("Operations", "Grid Change", NULL, "The operation of changing the spacing or color of the grid.");
        !            20: }
        !            21: 
        !            22: - saveBeforeChange
        !            23: {
        !            24:     oldSpacing = [graphicView gridSpacing];
        !            25:     oldGray = [graphicView gridGray];
        !            26:     oldVisible = [graphicView gridIsVisible];
        !            27:     oldEnabled = [graphicView gridIsEnabled];
        !            28:     return self;
        !            29: }
        !            30: 
        !            31: - undoChange
        !            32: {
        !            33:     newSpacing = [graphicView gridSpacing];
        !            34:     newGray = [graphicView gridGray];
        !            35:     newVisible = [graphicView gridIsVisible];
        !            36:     newEnabled = [graphicView gridIsEnabled];
        !            37: 
        !            38:     [[self changeManager] disableChanges:self];
        !            39:        [graphicView setGridSpacing:oldSpacing andGray:oldGray];
        !            40:        [graphicView setGridVisible:oldVisible];
        !            41:        [graphicView setGridEnabled:oldEnabled];
        !            42:     [[self changeManager] enableChanges:self];
        !            43:     return [super undoChange];
        !            44: }
        !            45: 
        !            46: - redoChange
        !            47: {
        !            48:     [[self changeManager] disableChanges:self];
        !            49:        [graphicView setGridSpacing:newSpacing andGray:newGray];
        !            50:        [graphicView setGridVisible:newVisible];
        !            51:        [graphicView setGridEnabled:newEnabled];
        !            52:     [[self changeManager] enableChanges:self];
        !            53:     return [super redoChange];
        !            54: }
        !            55: 
        !            56: - (BOOL)subsumeChange:change
        !            57: /*
        !            58:  * ChangeManager will call subsumeChange: when we are the last 
        !            59:  * completed change and a new change has just begun. We override
        !            60:  * the subsumeChange: because we want to consolidate multiple
        !            61:  * grid changes into a single change. For example, if the user
        !            62:  * selects the menu item "Show Grid" and then selects the menu
        !            63:  * item "Turn Grid On", we'll only leave a single GridChange in
        !            64:  * the ChangeManager's list of changes.Both changes can then be
        !            65:  * be undone and redone in one action.
        !            66:  */
        !            67: {
        !            68:     if ([change isKindOf:[GridChange class]]) {
        !            69:         [self saveBeforeChange];
        !            70:         return YES;
        !            71:     } else {
        !            72:         return NO;
        !            73:     }
        !            74: }
        !            75: 
        !            76: @end

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