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TRSSVGControl Class

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Provides a base class for controls which use an SVG for painting their look and feel. The control allows setting the active SVG element in the SVG; this is the element or group of elements that will be changing often and should not be prerendered (such as a compass needle). The control will automatically prerender the background and foreground (the non active element part) of the SVG.

Namespace: RSSVGControl

Name

Description

AbsoluteMatrix

Returns the combined transformation matrix for the control. This is the control's transformation matrix multiplied by all parent IRSGPControl control's transformation matrices.

ActiveSVGElement

Specifies the dynamic element in the SVG, the part that will be changing often. The ActiveSVGElement is not buffered when painting as it is assumed it will be changing. Set the ActiveSVGElement to tell the control which element or group of elements need to be redrawn every paint event.

The non-active svg elements are rendered either to the Background or Foreground Buffer.

Note
It is recommended that the active portion of the SVG not be too drawing intensive as it will slow painting.

Background

Contains the static background of the SVG compared to the ActiveSVGElement, i.e. the SVG elements that are rendered behind the ActiveSVGElement. The Background and Foreground are painted once from the SVG. When elements in the ActiveSVGElement group change, the Background and Foreground are not rendered again, significantly speeding up painting of the entire SVG.

Note
It is not recommended to change SVG elements in the background too often as it requires a complete rerendering of the background.

Buffered

Specifies whether to draw the SVG to a backbuffer and then copy that image to the canvas (default) or to draw directly on the canvas

Set the Buffered property to false to draw directly on the image canvas. This is generally not recommended, however, it may look better on mobile devices

Foreground

Contains the static foreground of the SVG compared to the ActiveSVGElement, i.e. the SVG elements that are rendered in front of the ActiveSVGElement. The Background and Foreground are painted once from the SVG. When elements in the ActiveSVGElement group change, the Background and Foreground are not rendered again, significantly speeding up painting of the entire SVG.

Note
It is not recommended to change SVG elements in the background too often as it requires a complete rerendering of the background.

Height

Represents property Height.

Matrix

Returns the transformation matrix of the control

NeedBuffers

Controls whether the Background and Foreground need to be rendered again in the Buffered paint process. Set the NeedBuffers property to True to force the buffers to be redrawn at the next paint event.

OnDrawing

Occurs just before drawing the current element and its children. The event fires after the canvas brush, pen, font, clipping, etc are set up but before the actual drawing.

OnDrawn

Occurs just after a SVG element is drawn. The event fires after drawing the current element and its children but before the canvas is returned to its initial state.

Opacity

Specifies the opacity or transparency of the SVG image. If Opacity is less than 1, then the SVG is displayed semi- transparent. If Opacity is 0, then the SVG is not displayed.

Quality

Controls the quality of the RSSVGControl.TRSSVGControl.Buffered painting of the SVG image. The value of quality can vary between 1 (low quality) to 8 (very high quality).

Note

This property controls the amount of oversampling performed in the buffered drawing. The offscreen buffers' dimensions are multiplied by the Quality value. Then, the offscreen buffers are downsampled when painting the control, providing anti-aliasing of the buffered drawing.
This property is intended for mobile applications. The quality on desktop FMX applications is already high and requires no extra memory.

Warning
Occasionally, oversampling can cause different output compared to the unbuffered output. The extra size of the buffers requires more triangles to output gradients and other elements. If this exceeds Embarcadero's limits, the element is not drawn.

Stretch

Defines if the control draws the SVG stretched to the complete bounds of the control (True) or draws the SVG to the maximum dimensions while respecting the aspect ratio of the SVG (False).

SVG

Contains the SVG that paints the appearance of the control. The control changes the SVG elements based on requirements of the control. For example, a descendant control could change a specific element's fill and stroke based on a Color property change.

Transform

Specifies the overall transformation to apply to the instrument image. For no transformation, set the Matrix to the RSIdentityMatrix

Width

Represents property Width.

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	Name	Description
	DoPaint	Represents method DoPaint.
	EnabledChanged	This method is called when the Enabled property changes. The SVG colors are rendered in grayscale when the control is disabled.
	GetAbsoluteMatrix	Returns the combined transformation matrix for the control. This is the control's transformation matrix multiplied by all parent IRSGPControl control's transformation matrices.
	GetDrawRect	Returns the rectangle where the SVG should be drawn. This is dependent on the current stretch value, the control's width and height, and the SVG's width and height.
	GetMatrix	Returns the transformation matrix of the control
	GetOpacity	Returns the Opacity of the control
	GetShapeRect(TObject,TRSRect)	Returns the rectangle for the control
	IsBuffered	Returns True if the instrument should be drawn to a offscreen bitmap
	LoadSVGResource(String)	Load the SVG from an embedded resource. This method initializes the ActiveSVGElement property and should be used to initialize any control fields (such as colors) that are dependant on the values in the SVG.
	ObjectChanged(TObject)	This method is called when an object property (such as Font) has changed and the control needs to respond to the change.
	Resize	Represents method Resize.
	SetOpacity(Single)	Sets the opacity of the control. If Opacity is less than 1, then the SVG is displayed semi- transparent. If Opacity is 0, then the SVG is not displayed.
	UpdateBuffers	Updates the Foreground and Background buffers with the non active elements of the SVG.

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TRSSVGControl Class

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