Ink Canvas Element

Summary ¶

	Ink Canvas
Info
Category:	Input Registration		AddIn:	Base Layer
Creator:	OkazoLab		Scope:	Parent event
Owns Snippets:	None		Usage:	Stimulus screen

Properties ¶

Name	Description	Constraints	Type	On runtime change
Settings
Reset On Onset	Defines whether the old canvas strokes and text recognition results are reset on the onset of the parent event	Normal..	Boolean
Normal Tip Mode	Specifies the mode of the pointing device as it interacts with the canvas	Normal..	enInkC..
Inverted Tip Mode	Specifies the mode of the inverted pointing device as it interacts with the canvas (e.g. with the inverted tip of a stylus)	Normal..	enInkC..
Drawing Attributes
Behold Pressure	Defines whether the thickness of a rendered stroke changes according the amount of pressure applied (if an input device can report a pressure)	Normal..	Boolean
Is Highlighter	Defines whether the rendered stroke looks like a highlighter (semi-transparent).	Normal..	Boolean
Pen Size	Defines a size of the drawing pen.	Normal..	clSize
Pen Color	Defines a color of the drawing pen.	Normal..	stColor
Drawn Color	Defines a color that highlights the currently drawing stroke. When a stroke is finished, it turns back to the pen color. No highlighting is applied, when the transparent color (0,255,255,255) is selected.	Normal..	stColor
Smoothing	Defines whether Bezier smoothing is used to render strokes.	Normal..	Boolean
Pen Shape	Defines a shape of the drawing pen. Assign 0 for rectangle and 1 for ellipse	Normal..	enPenS..
Canvas Background	Defines the background of the ink canvas.	Normal..	stColor
Actions
Clear Canvas Now	Set to true to clear canvas and erase all collected strokes.	Normal..	Boolean
Save Ink File Now	Assign a fully specified filename to save the current strokes to a file at runtime	Runtime Command..	String
Open Ink File Now	Assign a fully specified filename to load strokes from a file at runtime. Only the Ink Serialized Format (.isf) files are supported.	Runtime Command..	String
Recognize Text Now	Runtime command that performs text recognition on the current canvas content. The result is returned via the 'Recognized Text' property.	Runtime Command..	Boolean
Runtime Status
Stroke Number	Returns a number of drawn strokes	Normal..	Int32
Recognized Text	Return a recognized text in a result of the Recognize Text action	Status..	String
Recognition Confidence	Return a confidence rank in results of the Recognize Text action	Status..	String
Visual Appearance
Alpha Masking	Defines, whether the visual content is used to create an opacity mask on the event surface. If masking is on, the content's pixel luminance (or, its inverse) defines transparency within element's viewport. The alpha masking allows, for example, create transparent holes on the event surface.	Design Time..	Int32
AntiAliasing	if true, the rendered content will be antialiased for smoother visual appeariance. If false, rendering will be authentic to its source, e.g. a bitmap.	Normal..	Boolean
Position	Defines a position of the rendering viewport on the screen	Normal..	clPoint
Size	Defines a size of the element's rendering viewport on the screen	Normal..	clSize
Z Order	Indicates Z Order of the element on the given event	Status..	Int32
Pivot Point	Defines alignment of the pivot point (or, element's position) relative to element's rendering area. The pivot point sets the center of element's rotation and scale directions.	Normal..	stAlig..
Visible	Defines whether the element is visible	Normal..	Boolean
Rotation	Rotation angle in degrees	Normal..	Double
Effects
Transparent Color	The color of the original pixels of rendered content that will be set as transparent	Normal..	stColor
Transparent Tolerance	Tolerance ratio for choosing colors that become transparent. Zero means that effect is not applied, 1 denotes that all colors will become trasparent	Normal..	Int32
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 dont change the original pixels	Normal..	stColor
Opacity	Opacity of the rendered content	Normal..	Int32
Contrast	Contrast of the rendered content	Normal..	Int32
Brightness	Brightness the rendered content	Normal..	Int32
Saturation	Saturation of the rendered content	Normal..	Double
Pixelation	Pixelation of the rendered content	Normal..	Int32
Blurring	The radius used in the gaussian blur of rendered content, as a pixel-based factor. The default is 0 which means no blurring.	Normal..	Int32
Scrambling		Normal..	Double
Scrambling Grid Size	Defines a size of the scrambling grid	Normal..	clSize
Positional Jitter
Reset Jitter Now	Runtime command that resets the positional jitter.	Runtime Command..	Boolean
Current Jitter	Returns the current jitter	Status..	clPoint
Jitter Range	Defines a possible range for the random jitter. The range is centered to the position of the element.	Normal..	clSize
Test Jitter	Click to test the current jitter	Design Time..	Boolean
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

¶

Description ¶

Demo video ¶

Snapshots ¶

Experiment Run	After experiment Picture Stays in InkCanvas
Cat Recognized correctly	Recorgnized that user wrote wrong word

Practical Use ¶

Creating the Ink Canvas element ¶

1. Add a new Ink Canvas element to the chosen event.
2. Adjust the canvas area either in the event surface editor or via element's Position and Size properties.
3. Adjust other properties of the Ink Canvas canvas element. For example, you can define the canvas background, stroke color and different drawing modes.
4. Double-click on the canvas area in the event surface editor and try to draw several strokes for testing. Make a double-click again to exit the test mode.
5. Write code that resets the canvas, requests text recognition and records drawing results in accordance with a logic of your experiment. To control the element at runtime, create proxy variable for the element's properties.
6. Start the experiment. After the onset of the parent event the element becomes functional.
   

Saving the drawing results at runtime ¶

1. Add a new Ink Canvas element to the chosen event and prepare it as described above.
2. Create proxy variables for the following properties: 'Save Ink File Now' and 'Clear Canvas Now'.
3. Add the following code in a snippet that is called after a participant completes drawing:
   

   
   
   SaveInkFileNow="C:\\Data\\Participant_"+ParticipantCode+"_"+DrawingNumber+".csv";
   
   ClearCanvasNow=true;
   
   

   
   This code saves the collected stroke statistics and resets the made drawing. Note that you need to declare and adjust global variables ParticipantCode and DrawingNumber to form an unique file name (you can use other ID variables).
   

Using the Ink Canvas element to recognize handwritten text ¶

1. Add a new Ink Canvas element to the chosen event and prepare it as described above.
2. Create proxy variables for the following properties: 'Recognize Text Now', 'Recognized Text' and 'Recognition Confidence'.
3. Add the following code in a snippet that is called after a participant completes writing:
   

   
   
   RecognizeTextNow=true;
   
   

4. Add the following code in a subsequent snippet that is called after (importantly!) the 'RecognizeTextNow' snippet:
   

   
   
   string S=RecognizedText; // string S now contains a text recognized by the Ink Canvas;
   
   string C=RecognitionConfidence; // string C now contains one of the confidence ranks, e.g. 'week', 'average', 'strong'
   
   

   
   if you try to read the RecognizedText or RecognitionConfidence variables before or simultaneously with the 'RecognizeTextNow=true' command, the results wont be yet updated.
   

Notes ¶

• When the Ink Canvas element is used in the preview or debug modes, you may see flickering artefacts while doing drawing. Do not worry, these artefacts wont appear, when an experiment is run in he full screen mode.
• When the Ink Canvas element recognizes handwritten text, it considers all strokes made on the canvas from the left-top to the bottom-right. Thus, the recognition result may contain a text sentence, if multiple words are written on the canvas.
• When the Reset On Onset property is set to true, the canvas area (all existing strokes) is cleared on the onset of the parent event.