The CairoSurface class (gb.cairo) is the parent class of the CairoSurface classes below.
Surface is understood as a surface or just a surface for drawing or as an object on which you can draw. The class CairoPdfSurface represents a PDF file, CairoPsSurface a PostScript file and CairoSvgSurface an SVG file whose content is a scalable vector graphic. The three classes CairoPdfSurface, CairoPsSurface and CairoSvgSurface have all the properties and methods of the parent class CairoSurface.
The CairoSurface class has three properties:
| Property | Data type | Description |
|---|---|---|
| Path | String | Returns the path of the generated file. |
| Resolution | Float | Returns the resolution of the surface or sets the default resolution to 300 pixels/inch. |
| Status | Integer | Checks whether an error occurred for the surface used during drawing and then returns the error status. |
Table 25.1.9.2.1 : Properties of the CairoSurface class
An overview of the possible status values can be found in the overview of the constants for the Cairo class under the link → http://gambaswiki.org/wiki/comp/gb.cairo/cairo.
The CairoSurface class has these two methods:
| Method | Return type | Description |
|---|---|---|
| Finish ( ) | - | This function completes all operations for drawing on the surface and frees all references to external resources. |
| Save ( Path As String ) | Integer | Saves the content of the drawing area as a PNG file in the specified file path. The function returns an integer - a zero if successful. |
Table 25.1.9.3.1 : Methods of the CairoSurface class
Only the CairoPdfSurface class has the additional method CairoPdfSurface.Resize(..). It changes the size of a PDF surface for the current and other pages:
CairoPdfSurface.Resize ( Width As Float, Height As Float )
This function should only be called before drawing operations are carried out on the current page. If necessary, call this function immediately after creating the interface or immediately after completing a page (Cairo.ShowPage() or Cairo.CopyPage()).
You can generate a new CairoPdfSurface like this:
Dim hCairoPdfSurface As CairoPdfSurface hCairoPdfSurface = New CairoPdfSurface (Path As String,Width As Float,Height As Float [,Version As String])
A PDF surface with the specified size in millimetres is generated:
This creates a new CairoSvgSurface:
Dim hCairoSvgSurface As CairoSvgSurface hCairoSvgSurface = New CairoSvgSurface ( Path As String, Width As Float, Height As Float [ , Version As String ] )
An SVG surface with the specified size in millimetres is created:
A new CairoPsSurface object for drawing is generated as follows
Dim hCairoPsSurface As CairoPsSurface hCairoPsSurface = New CairoPsSurface ( Path As String, Width As Float, Height As Float [ , Encapsulated As Boolean, Level As String ] )
A PostScript surface with the specified size is generated: