The source
rectangle determines which part of the bitmap LEADTOOLS treats
as the source image. By default, it is the whole bitmap. (In fact, by
default, all four rectangles are initialized to the size of the bitmap.)Displaying an Image
Set the following properties (possibly at design time) to control the style of display:
For additional settings, refer to Using Special Effects When Painting. and Adding a Frame to the Control.
Use the following properties to implement automated scaling, positioning and scrolling of an image.
If you do not use the automated scaling properties, other properties and methods let you specify exactly which part of an image to paint and how big to make it.
When painting an image, LEADTOOLS uses the following four rectangles that determine how the image is scaled, positioned, and cropped:
The source
rectangle determines which part of the bitmap LEADTOOLS treats
as the source image. By default, it is the whole bitmap. (In fact, by
default, all four rectangles are initialized to the size of the bitmap.)
The destination
rectangle positions the displayed image relative to the LEAD control
and determines the displayed size. If the destination rectangle is larger
or smaller than the source rectangle, LEADTOOLS scales the image to fit
the destination rectangle. You can view the following illustrations in
a separate window:
|
|
|
|
|
The source
clipping rectangle limits the part of the source rectangle that
LEADTOOLS paints. This rectangle does not affect scaling. You can view
the following illustration in a separate window:
|
|
The destination
clipping rectangle limits the part of the destination rectangle
that LEADTOOLS paints. This rectangle does not affect scaling, but if
the image is scaled, you should set it to match the destination rectangle.
You can view the following illustration in a separate window:
|
|
If you set the AutoSetRects property to true, when a bitmap is loaded or resized, LEADTOOLS initializes all four rectangles to a 0, 0 position and to the same width and height as the bitmap. If you set the AutoScroll property, LEADTOOLS automatically adjusts the origin of the destination rectangles when the user scrolls the image.
The size of the LEAD control also can limit how much of the image is displayed. The way you size and position the LEAD control depends on your programming environment, but you can set the destination rectangle to fit the size of the control.
Use the following properties to get the current client area of the LEAD control. Typically, you would use these properties to fit the destination rectangle to the size of the control. These are basic properties which are not documented.
Height property
Left property
Top property
Width property
Use the following methods to set the rectangle specifications:
Alternatively, you can read or write the following properties that define the rectangles:
Occasionally, it is necessary to convert between bitmap coordinates and client area coordinates. LEADTOOLS provides the BitmapToClient and ClientToBitmap methods for converting coordinates. Each of these methods takes as parameters the X and Y coordinates to be converted, and updates the ConvertX and ConvertY properties with the newly converted coordinates.
Use the following method to force repainting of the image. (If the AutoRepaint property is set to TRUE, you do not have to force a repaint.)
Use the following method to force repainting of a specified rectangle in the LEAD control's client area.
Use the following properties and methods to apply window leveling to a 12 or 16-bit grayscale image. (Support for 12 and 16-bit grayscale images is available in Document/Medical toolkits only. Support for window leveling is available in Medical toolkits only.):