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Page Revision: 2011/07/20 13:48

GDI canvas is an element that allows you to create custom runtime graphics using the GDI+ functions.

Table of Contents [Hide/Show] Description Snapshots Practical Use Notes Properties     Generic properties

Description ¶

GDI+ is a powerful graphical platform in Windows, with thousands functions for drawing graphical primitives and bitmaps, managing colors and geometrical transforms (GDI+ overview). You can call these functions in your code snippets in order to draw a dynamic 2D graphical content in your experiment.

Snapshots ¶

Snapshot 1

Snapshot 2

Practical Use ¶

Using the element is very easy. By setting its position and size you define a rectangular area on the screen that represents a rendering canvas for drawing functions. Then you address the Graphics property of the element. This property provides you with the base GDI class which, in turn, possesses all available drawing functions. Now you call these functions directly like in this C# line:

 Graphics.DrawRectangle(new Pen(Color.Red), 20,20,248,162); 

When a snippet with GDI calls is completed the canvas element redraws its rendering canvas which also reappears on the screen if the parent event is active.

Notes ¶

1. The drawing coordinates in your code have to be inside of the range defined by the size of the GDI Canvas element in pixels, otherwise the drawn content will be cut off.
2. The GDI canvas element remembers its rendered state even if the parent event is deactivated and activated again. To clear the drawn graphics use the GDI Clear() function.
   

Properties ¶

Generic properties ¶

Name	Description	Attributes	Value Type
RunTime
Graphics	A reference of the base GDI+ class which implements all available drawing functions.	R	System.Drawing.Graphics

+=== Properties inherited from clVisualElement ===

Name	Description	Constraints	Value Type	Upon Runtime Change
VISUAL APPEARANCE
Alpha Masking	Defines whether the visual content rendered by this element will be used as an opacity mask which is applied onto the given event surface. The active opacity mask allows one to expose pixels of the parent event surface through a solid background of the given event. If the value is true, the darker pixels of the content will make more transparent holes on the entire event surface.	Design Time..	Boolean
AntiAliasing	If true, the rendered content will be anti-aliased for smoother visual appearance. If false, rendering will be authentic to its source, e.g. a bitmap.		Boolean	Visual Update..
Position	Defines the position of the element viewport on the screen. The position can be set in any of three coordinate systems: a) pixels, b) polar, c) central.		clPoint	Visual Update..
Size	Defines the size of the element viewport on the screen. The size can be set in any of three coordinate systems: a) pixels, b) visual degrees, c) 'relative-to-screen' size.		clSize	Visual Update..
Z Order	Indicates the current depth order of the element viewport on the surface of the parent event. The greatest number corresponds to the top position. The order can be changed by moving the element up and down in the element list.	Status..	Int32
Pivot Point	Defines the pivot point (coordinate and the rotation centers) within the element viewport.		stAlignment or Int32	Visual Update..
Visible	Defines whether the element is currently visible on the event surface. The property is convenient for switching visual content on and off.		Boolean	Visual Update..
Rotation	Defines the rotation angle (in degrees) of element viewport relative to the its pivot point.		Double in the range 0..360	Visual Update..
EFFECTS
Transparent Color	The color of the original pixels of rendered content that will be set as transparent.		stColor	Visual Update..
Transparency Tolerance	Tolerance ratio for choosing colors that become transparent. Zero means that effect is not applied, 1 denotes that all colors will become trasparent.		Int32, range (0..100)	Visual Update..
Color Mask	Produces a multiplicative combination of the original pixels and the selected mask color (except the alpha channel). The effect emulates a look through a colored glass. White or transparent mask color doesn't change the original pixels.		stColor	Visual Update..
Opacity	Opacity of the rendered content.		Int32, range (0..100)	Visual Update..
Contrast	Contrast of the rendered content.		Int32, range (-100..100)	Visual Update..
Brightness	Defines the brighness of the rendered content.		Int32, range (-100..100)	Visual Update..
Saturation	Saturation of the rendered content.		Double	Visual Update..
Pixelation	Defines the pixel scale of the rendering.		Int32, range (0..100)	Visual Update..
Blurring	The radius used in the gaussian blur of rendered content, as a pixel-based factor. The default is 0 which means no blurring.		Int32	Visual Update..
POSITIONAL JITTER
Reset Jitter	Set to true at runtime to reset the current positional jitter.	Runtime Command..	Boolean, set true for action	Visual Update..
Current Jitter	Jitter range, in pixels (non inclusive).	.	clSize	Visual Update..
Jitter Range	Jitter range, centered at the original position of the element.	.	clSize	Visual Update..

+=== Properties inherited from clElement === Inherited properties of clElement

Name	Description	Constraints	Value Type	Upon Change
Control
Is Enabled	If set to false the element is completely omitted when the experiment is run.	Design Time..	Boolean
Title	Title of the element.	Design Time..	String