SetScrollSizes( nMapMode, GetDocument( )->GetMyDocSize( ) )中的MSDN解释

 

void SetScrollSizes( int nMapMode, SIZEsizeTotal, const SIZE& sizePage = sizeDefault, const SIZE&sizeLine = sizeDefault );

Parameters

nMapMode

The mapping mode to set for this view. Possible values include:

Mapping ModeLogical UnitPositive y-axis Extends...MM_TEXT1 pixelDownwardMM_HIMETRIC0.01 mmUpwardMM_TWIPS1/1440 inUpwardMM_HIENGLISH0.001 inUpwardMM_LOMETRIC0.1 mmUpwardMM_LOENGLISH0.01 inUpward

All of these modes are defined by Windows. Two standard mapping modes,MM_ISOTROPIC and MM_ANISOTROPIC, are not used forCScrollView. The class library provides the SetScaleToFitSize member function for scaling the view to window size. Column three in the table above describes the coordinate orientation.

sizeTotal

The total size of the scroll view. The cx member contains the horizontal extent. Thecy member contains the vertical extent. Sizes are in logical units. Bothcx and cy must be greater than or equal to 0.

sizePage

The horizontal and vertical amounts to scroll in each direction in response to a mouse click in a scroll-bar shaft. Thecx member contains the horizontal amount. The cy member contains the vertical amount.

sizeLine

The horizontal and vertical amounts to scroll in each direction in response to a mouse click in a scroll arrow. Thecx member contains the horizontal amount. The cy member contains the vertical amount.

Remarks

Call SetScrollSizes when the view is about to be updated. Call it in your override of theOnUpdate member function to adjust scrolling characteristics when, for example, the document is initially displayed or when it changes size.

You will typically obtain size information from the view’s associated document by calling a document member function, perhaps calledGetMyDocSize, that you supply with your derived document class. The following code shows this approach:

SetScrollSizes( nMapMode, GetDocument( )->GetMyDocSize( ) );

Alternatively, you might sometimes need to set a fixed size, as in the following code:

SetScrollSizes( nMapMode, CSize(100, 100) );

You must set the mapping mode to any of the Windows mapping modes except MM_ISOTROPIC or MM_ANISOTROPIC. If you want to use an unconstrained mapping mode, call theSetScaleToFitSize member function instead of SetScrollSizes.

Example

void CScaleView::OnUpdate( ){   // ...   // Implement a GetDocSize( ) member function in    // your document class; it returns a CSize.   SetScrollSizes( MM_LOENGLISH, GetDocument( )->GetDocSize( ) );   ResizeParentToFit( );   // Default bShrinkOnly argument   // ...}