Leunsel: Initial page creation.

2026-06-27T01:12:49Z

Initial page creation.

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[[Category:Lua]]
{{Class|'''class''' CustomControl ''':''' WinControl}}

The CustomControl class represents a windowed control that exposes a Canvas for custom drawing.

CustomControl inherits from [[Lua:Class:WinControl|WinControl]], [[Lua:Class:Control|Control]], [[Lua:Class:Component|Component]], and [[Lua:Class:Object|Object]].

===Inheritance===
{|width="85%" cellpadding="10%" cellspacing="0" border="0"
!align="left"|Class
!align="left"|Inherits From
!style="width: 80%;background-color:white;" align="left"|Description
|-
|CustomControl
|WinControl
|Base class for windowed controls that support custom painting.
|-
|WinControl
|Control
|Base class for controls that have a window handle, can contain child controls, and can receive focus.
|-
|Control
|Component
|Base class for visual controls.
|-
|Component
|Object
|Base class for owned components.
|-
|Object
|None
|Base class for Lua-exposed objects.
|}

== Properties ==

{|width="85%" cellpadding="10%" cellspacing="0" border="0"
!align="left"|Property
!align="left"|Type
!style="width: 80%;background-color:white;" align="left"|Description
|-
|Canvas
|[[Lua:Class:Canvas|Canvas]]
|Read-only canvas object used for drawing on the control.
|-
|OnPaint
|Function
|Event handler that can be assigned to perform custom painting.
|}

== Methods ==

{|width="85%" cellpadding="10%" cellspacing="0" border="0"
!align="left"|Method
!align="left"|Return Type
!style="width: 80%;background-color:white;" align="left"|Description
|-
|getCanvas()
|[[Lua:Class:Canvas|Canvas]]
|Returns the Canvas object for the object that inherited from CustomControl.
|}

== Method Parameters ==

===getCanvas===
This method has no parameters.

== Examples ==

===Get the Canvas through the property===
<syntaxhighlight lang="lua" line highlight="4">
local form = createForm(false)
local paintBox = createPaintBox(form)

local canvas = paintBox.Canvas

print(canvas.ClassName)

form.destroy()
</syntaxhighlight>

===Get the Canvas through getCanvas===
<syntaxhighlight lang="lua" line highlight="4">
local form = createForm(false)
local paintBox = createPaintBox(form)

local canvas = paintBox.getCanvas()

print(canvas.ClassName)

form.destroy()
</syntaxhighlight>

===Assign an OnPaint event===
<syntaxhighlight lang="lua" line highlight="4">
local form = createForm(false)
local paintBox = createPaintBox(form)

paintBox.OnPaint = function(sender)
local canvas = sender.Canvas
canvas.TextOut(10, 10, "Custom painting")
end

form.show()
</syntaxhighlight>

===Draw a rectangle in OnPaint===
<syntaxhighlight lang="lua" line highlight="4,6">
local form = createForm(false)
local paintBox = createPaintBox(form)

paintBox.OnPaint = function(sender)
local canvas = sender.Canvas
canvas.Rectangle(10, 10, 150, 80)
end

form.show()
</syntaxhighlight>

===Draw text on the control===
<syntaxhighlight lang="lua" line highlight="4,6">
local form = createForm(false)
local paintBox = createPaintBox(form)

paintBox.OnPaint = function(sender)
local canvas = sender.Canvas
canvas.TextOut(10, 10, "Hello Canvas")
end

form.show()
</syntaxhighlight>

===Use the same handler for multiple controls===
<syntaxhighlight lang="lua" line highlight="8,9">
local form = createForm(false)
local paintBox1 = createPaintBox(form)
local paintBox2 = createPaintBox(form)

local function paintHandler(sender)
sender.Canvas.TextOut(10, 10, sender.Name)
end

paintBox1.OnPaint = paintHandler
paintBox2.OnPaint = paintHandler

form.show()
</syntaxhighlight>

===Use getCanvas inside a helper function===
<syntaxhighlight lang="lua" line highlight="2">
local function drawCaption(control, text)
local canvas = control.getCanvas()
canvas.TextOut(10, 10, text)
end

local form = createForm(false)
local paintBox = createPaintBox(form)

paintBox.OnPaint = function(sender)
drawCaption(sender, "Drawn by helper")
end

form.show()
</syntaxhighlight>

===Force repaint after changing state===
<syntaxhighlight lang="lua" line highlight="6,11">
local form = createForm(false)
local paintBox = createPaintBox(form)
local text = "Initial text"

paintBox.OnPaint = function(sender)
sender.Canvas.TextOut(10, 10, text)
end

text = "Updated text"

paintBox.repaint()

form.show()
</syntaxhighlight>

{{LuaSeeAlso}}

{{Forms}}

Lua:Class:CustomControl - Revision history

Leunsel: Initial page creation.