This field will return the left-most boundary of the viewport, relative to point (0, 0) of the scene graph. Transforms are taken into consideration when calculating this value.

This field will return the top-most boundary of the viewport, relative to point (0, 0) of the scene graph. Transforms are taken into consideration when calculating this value.

Defining an aspect ratio allows finer control over the position and scale of the viewport's content within its target area.

Viewport buffering is enabled by setting this field to true prior to initialisation. A Bitmap buffer will be created at the first drawing operation, and is available for the client to read from the Buffer field.

Potential reasons for enabling viewport buffering include: 1. Allows the client to read the rendered graphics directly from the Buffer; 2. Overall rendering will be faster if the content of the viewport rarely changes; 3. The use of multiple buffers can improve threaded rendering.

Buffering comes at a cost of using extra memory, and rendering may be less efficient if the buffered content changes frequently (e.g. is animated). Buffering also enforces overflow (clipping) restrictions, equivalent to Overflow being permanently set to HIDDEN.

Set the DragCallback field with a callback function to receive drag requests from the viewport's user input. When the user drags the viewport, the callback will receive the user's desired (X, Y) target coordinates. For unimpeded dragging, have the callback set the viewport's X and Y values to match the incoming coordinates, then redraw the scene.

The prototype for the callback function is as follows, where OriginX and OriginY refer to the (X,Y) position of the vector at initiation of the drag.

void function(*VectorViewport, DOUBLE X, DOUBLE Y, DOUBLE OriginX, DOUBLE OriginY)

Setting this field to NULL will turn off the callback.

It is required that the parent VectorScene is associated with a Surface for this feature to work.

The height of the viewport's target area is defined here as a fixed or scaled value. The default value is 100% for full coverage.

Choose an overflow option to enforce or disable clipping of the viewport's content. The default state is VISIBLE. Altering the overflow state affects both the X and Y axis. To set either axis independently, set OverflowX and OverflowY.

If the viewport's AspectRatio is set to SLICE then it will have priority over the overflow setting.

Choose an overflow option to enforce or disable clipping of the viewport's content. The default state is VISIBLE. If the viewport's AspectRatio is set to SLICE then it will have priority over the overflow setting.

This option controls the x axis only.

Choose an overflow option to enforce or disable clipping of the viewport's content. The default state is VISIBLE. If the viewport's AspectRatio is set to SLICE then it will have priority over the overflow setting.

This option controls the y axis only.

The area defined by (ViewX,ViewY) and (ViewWidth,ViewHeight) declare the source area covered by the viewport. The rendered graphics in the source area will be repositioned and scaled to the area defined by (X,Y) and (Width,Height).

The area defined by (ViewX,ViewY) and (ViewWidth,ViewHeight) declare the source area covered by the viewport. The rendered graphics in the source area will be repositioned and scaled to the area defined by (X,Y) and (Width,Height).

The area defined by (ViewX,ViewY) and (ViewWidth,ViewHeight) declare the source area covered by the viewport. The rendered graphics in the source area will be repositioned and scaled to the area defined by (X,Y) and (Width,Height).

The area defined by (ViewX,ViewY) and (ViewWidth,ViewHeight) declare the source area covered by the viewport. The rendered graphics in the source area will be repositioned and scaled to the area defined by (X,Y) and (Width,Height).

The width of the viewport's target area is defined here as a fixed or scaled value. The default value is 100% for full coverage.

The display position targeted by the viewport is declared by the (X,Y) field values. Coordinates can be expressed as fixed or scaled pixel units.

If an offset from the edge of the parent is desired, the XOffset field must be defined. If a X and XOffset value are defined together, the width of the viewport is computed on-the-fly and will change in response to the parent's width.

The display position targeted by the viewport is declared by the (X,Y) field values. Coordinates can be expressed as fixed or scaled pixel units.

If an offset from the edge of the parent is desired, the XOffset field must be defined. If the X and XOffset values are defined together, the width of the viewport is computed on-the-fly and will change in response to the parent's width.

The display position targeted by the viewport is declared by the (X,Y) field values. Coordinates can be expressed as fixed or scaled pixel units.

If an offset from the edge of the parent is desired, the YOffset must be defined. If the Y and YOffset values are defined together, the height of the viewport is computed on-the-fly and will change in response to the parent's height.

The display position targeted by the viewport is declared by the (X,Y) field values. Coordinates can be expressed as fixed or scaled pixel units.

If an offset from the edge of the parent is desired, the YOffset must be defined. If a Y and YOffset value are defined together, the height of the viewport is computed on-the-fly and will change in response to the parent's height.