GDI+: GdipGetImageBounds

[José Roca]

The following example creates an Image object based on a metafile and then draws the image. Next, the code calls the GdipGetBounds function to get the bounding rectangle for the image. The code makes two attempts to display 75 percent of the image. The first attempt fails because it specifies (0, 0) for the upper-left corner of the source rectangle. The second attempt succeeds because it uses the X and Y data members returned by GdipGetBounds to specify the upper-left corner of the source rectangle.

C++

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VOID Example_GetBounds(HDC hdc)
{
   Graphics graphics(hdc);

   Image image(L"SampleMetafile2.emf");
   graphics.DrawImage(&image, 0, 0);

   // Get the bounding rectangle for the image (metafile).
   RectF boundsRect;
   Unit unit;
   image.GetBounds(&boundsRect, &unit);

   // Attempt to draw 75 percent of the image.
   // Less than 75 percent of the image will be visible because the
   // upper-left corner of the image's bounding rectangle is not (0, 0).
   RectF dstRect(250.0f, 0.0f, 100.0f, 50.0f);
   graphics.DrawImage(
      &image,
      dstRect,                  // destination rectangle
      0.0f, 0.0f,               // upper-left corner of source rectangle
      0.75f*boundsRect.Width,   // width of source rectangle
      boundsRect.Height,        // height of source rectangle
      UnitPixel);

   // Draw 75 percent of the image.
   dstRect.Y = 80.0f;
   graphics.DrawImage(
      &image,
      dstRect,                       // destination rectangle
      boundsRect.X, boundsRect.Y,    // upper-left corner of source rectangle
      0.75f*boundsRect.Width,        // width of source rectangle
      boundsRect.Height,             // height of source rectangle
      UnitPixel);
}


PowerBASIC

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SUB GDIP_GetImageBounds (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pImage AS DWORD
   LOCAL strFileName AS STRING
   LOCAL boundsRect AS RECTF
   LOCAL unit AS LONG

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create an Image object, and then clone it.
   strFileName = UCODE$("climber.emf")
   hStatus = GdipLoadImageFromFile(STRPTR(strFileName), pImage)

   ' // Draw the image.
   hStatus = GdipDrawImage(pGraphics, pImage, 0, 0)

   ' // Get the bounding rectangle for the image (metafile).
   hStatus = GdipGetImageBounds(pImage, boundsRect, unit)

   ' // Attempt to draw 75 percent of the image.
   ' // Less than 75 percent of the image will be visible because the
   ' // upper-left corner of the image's bounding rectangle is not (0, 0).
   hStatus = GdipDrawImagePointRect(pGraphics, pImage, 250, 0, 100, 50, 0.75 * boundsRect.Width, boundsRect.Height, %UnitPixel)

   ' // Draw 75 percent of the image.
   hStatus = GdipDrawImagePointRect(pGraphics, pImage, 250, 80, boundsRect.x, boundsRect.y, 0.75 * boundsRect.Width, boundsRect.Height, %UnitPixel)

   ' // Cleanup
   IF pImage THEN GdipDisposeImage(pImage)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB