GDI Resources

FiveWin wraps the Windows GDI (Graphics Device Interface) objects into Harbour classes. These objects represent fonts, brushes, cursors, icons, bitmaps, and images. All GDI resources must be released when no longer needed by calling :End() to prevent resource leaks. This page also covers TIni (INI file management) and TReg32 (Windows Registry access).

Resource Lifecycle

TFont

Fuente: source/classes/font.prg

Key DATA Members

Key Methods

Example

#include "FiveWin.ch"

function Main()

   local oFont, oFontBig, oFontItalic

   // Standard definition via command
   DEFINE FONT oFont NAME "Segoe UI" SIZE 0, -14

   // Bold variant
   DEFINE FONT oFontBig NAME "Segoe UI" SIZE 0, -20 BOLD

   // Italic via method
   oFontItalic := oFont:Italic( .T. )

   // Use in a dialog
   DEFINE DIALOG oDlg TITLE "Font Demo" SIZE 400, 200 FONT oFont
   @ 1, 1 SAY "Normal text" OF oDlg
   @ 2, 1 SAY "Bold text" OF oDlg FONT oFontBig
   @ 3, 1 SAY "Italic text" OF oDlg FONT oFontItalic
   ACTIVATE DIALOG oDlg CENTER

   // Font picker
   // local oChosen := oFont:Choose()

   oFont:End()
   oFontBig:End()
   oFontItalic:End()

return nil

TBrush

Fuente: source/classes/brush.prg

Key DATA Members

Brush Styles

Example

#include "FiveWin.ch"

function Main()

   local oWnd, oBrush

   // Solid color brush
   DEFINE BRUSH oBrush COLOR nRGB( 30, 40, 60 )

   // Hatch pattern brush
   // DEFINE BRUSH oBrush STYLE "DIAGCROSS" COLOR CLR_BLUE

   // Bitmap brush
   // DEFINE BRUSH oBrush FILE "marble.bmp"

   DEFINE WINDOW oWnd TITLE "Brush Demo" BRUSH oBrush
   ACTIVATE WINDOW oWnd

   oBrush:End()

return nil

TCursor

TCursor wraps Windows cursor handles. Predefined cursors can be loaded by name, or custom cursors from resource files.

Example

#include "FiveWin.ch"

function Main()

   local oCursor

   // Predefined cursor
   DEFINE CURSOR oCursor HAND

   // From resource
   // DEFINE CURSOR oCursor RESOURCE "MyCursor"

   // Assign to a control
   // oBtn:oCursor := oCursor

   oCursor:End()

return nil

TIcon

TIcon wraps Windows icon handles (HICON). Icons can be loaded from resources compiled into the executable or from .ico files on disk.

Example

#include "FiveWin.ch"

function Main()

   local oWnd, oIcon

   // From resource (compiled into .exe)
   DEFINE ICON oIcon RESOURCE "APPICON"

   // From file
   // DEFINE ICON oIcon FILE "myapp.ico"

   DEFINE WINDOW oWnd TITLE "Icon Demo" ICON oIcon
   ACTIVATE WINDOW oWnd

   oIcon:End()

return nil

TBitmap

Fuente: source/classes/bitmap.prg

TBitmap is a control that displays bitmap images (BMP, PNG, JPG, GIF, ICO). It extends TControl, so it can be placed on windows and dialogs. Supports scrolling, stretching, transparency, and alpha blending.

Key DATA Members

Key Methods

Example

#include "FiveWin.ch"

function Main()

   local oDlg, oBmp

   DEFINE DIALOG oDlg TITLE "Bitmap Demo" SIZE 600, 400

   @ 1, 1 BITMAP oBmp FILE "photo.bmp" OF oDlg SIZE 250, 180 STRETCH

   // or from reFuente:
   // @ 1, 1 BITMAP oBmp RESOURCE "LOGO" OF oDlg SIZE 250, 180

   ACTIVATE DIALOG oDlg CENTER

return nil

TImage

Fuente: source/classes/image.prg

TImage extends TBitmap with FreeImage library support, enabling loading and saving of many image formats: BMP, PNG, JPEG, GIF, TIFF, WebP, ICO, PSD, RAW, and more. It can also load images from URLs.

Additional Methods (beyond TBitmap)

FreeImage DLL

TImage requires freeimage.dll (32-bit) or freeimage64.dll (64-bit) in the application directory or system PATH.

Example

#include "FiveWin.ch"

function Main()

   local oDlg, oImg

   DEFINE DIALOG oDlg TITLE "Image Demo" SIZE 800, 600

   // Load any format (PNG, JPG, GIF, WebP, etc.)
   @ 1, 1 IMAGE oImg FILE "photo.png" OF oDlg SIZE 350, 250 STRETCH

   // Load from URL (after dialog init)
   // oImg:LoadFromURL( "https://example.com/image.jpg" )

   // Save to different format
   // oImg:SaveImage( "output.jpg", FIF_JPEG, 85 )

   // Rotate
   // oImg:RotateImage( 90 )

   ACTIVATE DIALOG oDlg CENTER

return nil

TIni

Fuente: source/classes/ini.prg

TIni manages Windows INI configuration files. It uses the Windows API Funciones GetPrivateProfileString() and WritePrivateProfileString() for reliable INI file access.

Key DATA Members

Methods

Example

#include "FiveWin.ch"

function Main()

   local oIni, cUser, nPort, lDebug

   oIni := TIni():New( "myapp.ini" )

   // Read settings (with defaults)
   oIni:Get( "Database", "Server",   "localhost", @cServer )
   oIni:Get( "Database", "Port",     3306,        @nPort )
   oIni:Get( "App",      "Debug",    "N",         @cDebug )

   lDebug := ( cDebug == "Y" )

   // Write settings
   oIni:Set( "App", "LastRun", DToC( Date() ) + " " + Time() )
   oIni:Set( "App", "Version", FWVersion() )

   // Delete
   oIni:DelEntry( "Temp", "CacheFile" )

   ? "Server:", cServer, "Port:", nPort

return nil

This creates/reads an INI file like:

[Database]
Server=localhost
Port=3306

[App]
Debug=N
LastRun=03/24/2026 14:30:45
Version=FWH 26.05

TReg32

Fuente: source/classes/reg32.prg

TReg32 provides read/write access to the Windows Registry. It wraps the Windows Registry API Funciones (RegOpenKeyEx, RegQueryValueEx, RegSetValueEx, etc.).

Key DATA Members

Methods

Root Key Constants

Example

#include "FiveWin.ch"

#define HKEY_CURRENT_USER  2147483649

function Main()

   local oReg, cValue := ""

   // Read a registry value
   oReg := TReg32():New( HKEY_CURRENT_USER, ;
      "Software\Microsoft\Windows\CurrentVersion\Themes\Personalize" )

   if oReg:nError == 0
      oReg:Get( "AppsUseLightTheme", @cValue )
      ? "Dark mode:", iif( cValue == Chr(0), "Yes", "No" )
      oReg:Close()
   endif

   // Create and write a value
   oReg := TReg32():Create( HKEY_CURRENT_USER, "Software\MyApp" )
   if oReg:nError == 0
      oReg:Set( "LastRun", DToC( Date() ) + " " + Time() )
      oReg:Set( "Version", FWVersion() )
      oReg:Close()
   endif

   // Read it back
   oReg := TReg32():New( HKEY_CURRENT_USER, "Software\MyApp" )
   if oReg:nError == 0
      oReg:Get( "LastRun", @cValue )
      ? "Last run:", cValue
      oReg:Close()
   endif

return nil

Resource Management Best Practices

• Always call :End() on GDI resources (TFont, TBrush, TIcon, TBitmap, TImage) when you are done with them. Windows has a limited pool of GDI handles.
• Font caching: TFont internally caches fonts. Creating the same font twice returns the same object with an incremented reference count. Calling :End() decrements the count and only frees the handle when it reaches zero.
• Brush for windows: When assigning a brush to a window, the window takes ownership. The brush is freed when the window is destroyed.
• TIni and TReg32 do not use GDI handles, but TReg32:Close() should be called to release the registry key handle.
• Use GDI_GetObjectCount() during development to monitor GDI handle usage and detect leaks.