CreateBrushGradientLinear - ProGUI Reference Manual

Syntax

Brush = CreateBrushGradientLinear(StartX.d, StartY.d, EndX.d, EndY.d, StartColor.l, StartOpacity.f, EndColor.l, EndOpacity.f, StartPosition.f=0, EndPosition.f=1)

Description

Creates a linear gradient brush that blends colors along a straight line defined by start and end points. This version creates a simple two-color gradient. For more complex gradients with multiple colors, use CreateBrushGradientLinearEx() or add stops with BrushGradientAddColor().

Parameters

StartX.d, StartY.d
The coordinates (in DIPs relative to the drawing origin) of the starting point of the gradient line.

EndX.d, EndY.d
The coordinates (in DIPs relative to the drawing origin) of the ending point of the gradient line.

StartColor.l
The color (RGB value) at the start of the gradient.

StartOpacity.f
The opacity (0.0 to 1.0) at the start of the gradient.

EndColor.l
The color (RGB value) at the end of the gradient.

EndOpacity.f
The opacity (0.0 to 1.0) at the end of the gradient.

StartPosition.f (optional)
The relative position (0.0 to 1.0) along the gradient line where the `StartColor` is fully opaque. Default is 0.0 (the very beginning).

EndPosition.f (optional)
The relative position (0.0 to 1.0) along the gradient line where the `EndColor` is fully opaque. Default is 1.0 (the very end).

Return Value

Returns a handle to the newly created linear gradient brush object if successful, or #Null if the brush could not be created.

Remarks

The gradient transitions between `StartColor` (at `StartPosition`) and `EndColor` (at `EndPosition`) along the line defined by (`StartX`, `StartY`) and (`EndX`, `EndY`). The extend mode (BrushSetExtendMode) determines how the gradient behaves outside the defined start and end points. The brush can be transformed using BrushSetPosition(), BrushSetScale(), and BrushSetRotation(). Remember to free the brush using FreeBrush().

Example

IncludeFile "ProGUI_PB.pbi"

Global MyGradient

Procedure DrawHandler(Window, EventType, *EventData.PG_EventDraw)
  DrawClear(RGB(240, 240, 240), 1)
  ; Fill a rectangle using the gradient brush
  DrawBoxFill(50, 50, 300, 200, MyGradient)
EndProcedure

StartProGUI()

MyWindow = CreateWindow(0, 0, 400, 300, "Linear Gradient Brush")

If MyWindow
  ; Create a horizontal gradient from blue (left) to green (right)
  ; The gradient line goes from x=50 to x=350 at y=0 (relative to where it's drawn)
  MyGradient = CreateBrushGradientLinear(50, 0, 350, 0, RGB(0, 0, 255), 1.0, RGB(0, 255, 0), 1.0)
   
  If MyGradient
    ; Set extend mode to repeat (optional)
    ; BrushSetExtendMode(MyGradient, #PG_Brush_ExtendMode_Repeat, #PG_Brush_ExtendMode_Repeat)

    AddEventHandler(MyWindow, #PG_Event_Draw, @DrawHandler())
    WindowShow(MyWindow, #True, #PG_Window_ScreenCentered)

    Repeat
        Event = WaitWindowEvent()
    Until Event = #PB_Event_CloseWindow

    FreeBrush(MyGradient) ; Free the brush
  EndIf
EndIf

StopProGUI()

Supported OS

Windows, Linux