Miscellaneous Graphics Class Methods in GDI+


This article has been excerpted from book "Graphics Programming with GDI+".

The Graphics class provides more than just draw and fill methods. Miscellaneous methods are defined in Table 3.6. Some of these methods are discussed in more detail later.

The Clear Method

The Clear method clears the entire drawing surface and fills it with the specified background color. It takes one argument, of type Color. To clear a form, an application passes the form's background color. The following code snippet uses the Clear method to clear a form.


            form.Graphics g = this.CreateGraphics();
            g.Clear(this.BackColor);
            g.Dispose();


Figure 3.39.jpg

FIGURE 3.39: Filling a polygon
Figure 3.40.jpg
FIGURE 3.40: Filling rectangle

TABLE 3.6: Some miscellaneous Graphics methods


Methods Description

AddMetafileComment

Adds a comment to a Metafile object.

Clear

Clears the entire drawing surface and fills it with the specified background color.

ExcludeClip

Updates the clip region to exclude the area specified by a Rectangle structure.

Flush

Forces execution of all pending graphics operations and returns immediate without waiting for the operations to finish.

FromHdc

Create a new Graphics object from a device context handle.

FromHwnd

Creates a new Graphics object from a window handle.

FromImage

Creates a new Graphics object from an Image object.

GetHalftonePalette

Returns a handle to the current Windows halftone palette.

GetHdc

Returns the device context handle associated with a Graphics object.

GetNearestColor

Returns the nearest color to the specified Color structure.

IntersectClip

Updates the clip region of a Graphics object to the intersection of the current clip region and a Rectangle structure.

IsVisible

Returns true if a point is within the visible clip region.

MeasureCharacterRanges

Returns an array of Region objects, each of which bounds a range of character positions within a string.

MeaureString

Measures a string when drawn with the specified Font object.

MultiplyTransform

Multiplies the world transformation and the Matrix object.

ReleaseHdc

Release a device context handle obtained by a previous call to the GetHdc method.

ResetClip

Resets the clip region to an infinite region.

ResetTransform

Resets the world transformation matrix to the identity matrix.

Restore

Restores the state of a Graphics object to the state represented by a GraphicsState object. Takes GraphicsState as input, removes the information block from the stack, and restores the Graphics object to the state it was in when it was saved.

RotateTransform

Applies rotation to the transformation matrix.

Save

Saves the information block of a Graphics object. The information block stores the state of the Graphics object. The Save method returns a GraphicsState object that identifies the information block.

ScaleTransform

Applied the specified scaling operation to the transformation matrix.

SetClip

Sets the clipping region to the Clip property.

TransformPoints

Transforms an array of points from one coordinate space to another using the current world and page transformations.

TranslateClip

Translates the clipping region by specified amounts in the horizontal and vertical directions.

TranslateTransform

Prepares the specified translation to the transformation matrix.


Conclusion

Hope the article would have helped you in understanding Miscellaneous Graphics Class Methods in GDI+. Read other articles on GDI+ on the website.

bookGDI.jpg This book teaches .NET developers how to work with GDI+ as they develop applications that include graphics, or that interact with monitors or printers. It begins by explaining the difference between GDI and GDI+, and covering the basic concepts of graphics programming in Windows.

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