Unit Views: Views::FillGradientPath

Reference for the Mosaic class Views::FillGradientPath

Views::FillGradientPath
Embedded FillRule FlipY Gradient Offset Opacity Path Quality Visible

Core::RectView
Bounds

Core::View
Layout Owner StackingPriority
AdjustDrawingArea() ArrangeView() ChangeViewState() CursorHitTest() Draw() GetClipping() GetExtent() GetRoot() HandleEvent() MoveView()

The class Views::FillGradientPath provides a kind of view specialized to draw a filled polygon by using a complex linear or radial gradient. The shape of the polygon (the coordinates of the line segments) is provided in a Graphics::Path object assigned to the property Path. The position and the size of the area to display the path are determined by the property Bounds. The color gradient information is provided in a Graphics::LinearGradient or Graphics::RadialGradient object assigned to the property Gradient.

The property FillRule determines the algorithm to decide which parts of complex nested paths should be considered as filled and which are empty. With the property FlipY and Offset you can control the orientation and the origin position of the path coordinate system. Finally, the property Quality determines whether the paths is rasterized with or without antialiasing.

The visibility of the filled path is controlled by the properties Visible and Embedded. In particular the property Embedded can determine whether the corresponding view is limited (== embedded) to the boundary of a sibling Core::Outline view or not. The embedding of views within a Core::Outline allows a kind of sub-groups within the GUI component itself. Very useful for any kind of scrollable lists, menus, etc. Furthermore, the property Opacity can be used to modulate the transparency of the view.

property bool Embedded = false;

The property 'Embedded' controls how the view should appear and behave within its superior Owner. If this property == 'true', the affected view will be embedded (limited) to the boundary of a preceding Core::Outline sibling view. This is as if the view had been embedded within this outline. Beside the appearance limitation of the outline boundary, the outline also provides more sophisticated arrangement mechanisms and the content scrolling. It is therefore useful to create scrollable menus or lists.

If this property is 'false', the view is considered as a regular view of its Owner - it doesn't belong to any outline.

property Graphics::FillRule FillRule = Graphics::FillRule.EvenOdd;

The property 'FillRule' determines the modes how complex polygons consisting of nested paths are filled. The possible values are:

EvenOdd: Fills the path areas alternately depending on the nesting level of the closed paths. An area is considered as filled if the number of path segments between a point lying inside the area and any point outside the entire shape is odd. If the number of path segments is even, the area is not filled.
NonZero: Fills the path areas depending on the nesting level of the closed paths and their winding direction. An area is considered as filled when counting the path segments between a point lying inside the area and any point outside the entire shape the resulting value is not zero, whereby paths with positive winding direction increment the value while paths with negative winding decrement it. If the counter value is 0, the area is not filled.

property bool FlipY = false;

The property 'FlipY' controls the vertical orientation and the position of the origin of the coordinate system of the Path assigned to this view.

If this property is 'false', the coordinates provided within the Path object are assumed as being relative to the top-left corner of the Bounds area with the Y-axis pointing downwards. If the property FlipY is 'true', the coordinates are relative to the bottom-left corner with the positive Y-axis pointing upwards. Please note, the origin position can additionally be moved by using the property Offset.

property Graphics::Gradient Gradient = null;

The property 'Gradient' refers to an object containing the color information of the gradient. At the runtime, when the content of the associated gradient object changes, the view is updated automatically.

property point Offset = <0,0>;

The property 'Offset' specifies an additional displacement to add to the coordinates provided within the Path object when the path is rasterized on the screen. Changing this property allows the view to scroll the rasterized image of the path.

property int32 Opacity = 255;

The property 'Opacity' controls the translucence of the view. This property can take values in range of 0 .. 255. If the value is 255, the view will appear with its full opacity. The value equal to zero results in a fully transparent view. Other values in the range 1 .. 254 show a semitransparent view.

property Graphics::Path Path = null;

The property 'Path' refers to an object containing the coordinates of the path to fill. From the path data the view rasters a filled polygon. At the runtime, when the content of the associated path object changes, the view is updated automatically.

The coordinates provided within the path object are assumed as being relative to the top-left corner of the Bounds area with the Y-axis pointing downwards. If the property FlipY is 'true', the coordinates are relative to the bottom-left corner with the positive Y-axis pointing upwards. This origin can additionally be moved by using the property Offset.

property bool Quality = true;

The property 'Quality' determines whether the path rasterization should be performed with an additional antialiasing. The usage of the antialiasing produces better and smooth outputs. Without antialiasing the edges of the path appear with steps. Depending on the underlying graphics system, an active antialiasing may impact the resulting performance. Therefore it's up to you to decide which part of the GUI should appear with the higher quality. To activate the antialiasing assign 'true' to this property.

property bool Visible = true;

The property 'Visible' determines the visibility state of the view. Invisible views will not appear on the screen. Whether a view is really visible depends on the visibility of its Owner and the position of the view within the owners boundary area.