Zooming In on a Selection (C++ Builder 4.0)
Take the following steps to add code that lets you select an area with a mouse, and zoom in on the selected area.
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1. |
Start with the project that you created in Loading and Displaying an Image. |
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2. |
Handle the LEADRasterView1 control's OnMouseDown2 event, and code LEADRasterView1MouseDown2 as follows: |
void __fastcall TForm1::LEADRasterView1MouseDown2(TObject
*Sender,
short Button, short Shift, long x, long y)
{
//Enable AutoRubberBand
LEADRasterView1->AutoRubberBand
= true;
LEADRasterView1->MousePointer
= 2;
}
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3. |
Code the LEADRasterView1 control's Rubberband procedure, as the following: |
void __fastcall TForm1::LEADRasterView1RubberBand
(TObject *Sender)
{
int zoomleft;
int zoomtop;
int zoomwidth;
int zoomheight;
LEADRasterView1->MousePointer
= 0;
//Zoom in on the selection
zoomleft = LEADRasterView1->RubberBandLeft;
zoomtop = LEADRasterView1->RubberBandTop;
zoomwidth = LEADRasterView1->RubberBandWidth;
zoomheight = LEADRasterView1->RubberBandHeight;
//Zoom in on the rectangle defined by the rubberband
LEADRasterView1->ZoomToRect
(zoomleft, zoomtop, zoomwidth, zoomheight);
LEADRasterView1->Refresh () ;
}
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4. |
Run your program to test it. |