LCLIntf unit

Contains WinAPI-like functions for Delphi compatibility.

This unit was created for Delphi compatibility. It contains selected functions from the Delphi Windows unit, which finally are implemented in the widgetsets.

For LCL users:

The functions can be used to make porting of Delphi applications easier, and are not 100% emulating WinAPI functions, not even under windows. They were implemented and tested with some common Delphi libraries. The LCL contains many extra functions that the Delphi VCL does not have.

Some functions are not exactly Delphi or WinAPI compatible.

For example: Instead of using the common Windows functions SaveDC and RestoreDC use the Canvas.SaveHandleState and Canvas.RestoreHandleState.

Procedures and functions

`AddEventHandler`	function
`AddPipeEventHandler`	function
`AddProcessEventHandler`	function
`AdjustWindowRectEx`	function
`AllocateHWnd`	function
`AngleChord`	function	Draws a filled Chord described by two angles.
`Arc`	function	Draws an elliptical curve.
`AskUser`	function
`BeginPaint`	function	Start painting in a window.
`BitBlt`	function	Copies a section of a Canvas to another one, performing a raster operation (ROP).
`CallDefaultWndHandler`	procedure
`CallNextHookEx`	function	Calls the next procedure in the hook chain.
`CallWindowProc`	function	Calls another Window procedure, to handle a message.
`CharLower`	function
`CharLowerBuff`	function
`CharUpper`	function
`CharUpperBuff`	function
`ClientToScreen`	function	Converts (relative) Client coordinates into absolute Screen coordinates.
`ClipboardFormatNeedsNullByte`	function
`ClipboardFormatToMimeType`	function
`ClipboardGetData`	function
`ClipboardGetFormats`	function
`ClipboardGetOwnerShip`	function
`ClipboardRegisterFormat`	function
`CombineRgn`	function	Combines two regions.
`CopyRect`	function
`CreateBitmap`	function	Creates a bitmap object.
`CreateBrushIndirect`	function	Creates a brush object (bitmap).
`CreateBrushWithRadialGradient`	function
`CreateCaret`	function	Creates the Caret (text cursor) for the specified windowed control.
`CreateCompatibleBitmap`	function	Creates a bitmap that is compatible with the given DC.
`CreateCompatibleDC`	function	Creates an memory Device Context, compatible with the device of the given DC.
`CreateDIBitmap`	function	Creates a Device Dependent Bitmap (DDB) from a Device Independent Bitmap (DIB).
`CreateDIBSection`	function	Creates a bitmap into which the application can write.
`CreateEllipticRgn`	function	Creates an elliptic region.
`CreateEllipticRgnIndirect`	function
`CreateEmptyRegion`	function
`CreateFont`	function
`CreateFontIndirect`	function	Creates a logical font, selectable into any DC.
`CreateFontIndirectEx`	function	Creates a logical font, selectable into any DC. Allows for a long font name.
`CreateIconIndirect`	function	Creates an icon or cursor.
`CreatePalette`	function	Creates a logical palette, selectable into any DC.
`CreatePatternBrush`	function	Creates a logical brush, selectable into any DC.
`CreatePen`	function
`CreatePenIndirect`	function	Creates a logical Pen, selectable into any DC.
`CreatePixmapIndirect`	function
`CreatePolygonRgn`	function	Creates a polygonal region.
`CreateRectRgn`	function	Creates a rectangular region.
`CreateRectRgnIndirect`	function
`CreateRegionCopy`	function
`CreateRoundRectRgn`	function	Creates a rectangular region with rounded corners.
`CreateRubberBand`	function
`CreateSolidBrush`	function
`CreateStandardCursor`	function
`DCClipRegionValid`	function
`DeallocateHWnd`	procedure
`DeleteCriticalSection`	procedure	Deletes an un-owned critical section.
`DeleteDC`	function	Deletes a device context created by CreateDC.
`DeleteObject`	function	Frees a GDI object.
`DestroyCaret`	function	Destroys the caret but does not free the bitmap.
`DestroyCursor`	function	Destroys a mouse cursor.
`DestroyIcon`	function	Destroys an icon.
`DestroyRubberBand`	procedure
`DPtoLP`	function	Converts an array of Device Points (coordinates) into Logical Points.
`DrawDefaultDockImage`	procedure
`DrawEdge`	function	Draws one or more edges for a rectangle.
`DrawFocusRect`	function	Draws a focus rectangle on the specified device context.
`DrawFrameControl`	function	Draws a window frame for a control of the specified type in a given state.
`DrawGrid`	procedure	Draws the grid separator lines between columns and rows with the specified width and height.
`DrawText`	function	Draws formatted text on the specified device context.
`Ellipse`	function	Draws a filled circle or ellipse, bounded by a rectangle.
`EnableScrollBar`	function	Enables or disables the arrows of a scroll bar control, or of the scroll bars of a window.
`EnableWindow`	function	Enables or disables mouse and keyboard input to the specified window or control.
`EndPaint`	function	Ends painting a window, started with BeginPaint.
`EnterCriticalSection`	procedure	Enters a critical section.
`EnumDisplayMonitors`	function	Invokes a callback function for every available display monitor.
`EnumFontFamilies`	function	Invokes a callback function for every font available on a specified device.
`EnumFontFamiliesEx`	function	Invokes a callback function for every available font that matches certain criteria.
`EqualRect`	function	Returns True when the rectangles are identical.
`EqualRgn`	function
`ExcludeClipRect`	function	Excludes a rectangle from the clipping region, i.e. allows one to paint within the rectangle.
`ExcludeClipRgn`	function
`ExtCreatePen`	function	Creates a logical pen, selectable into any DC.
`ExtSelectClipRGN`	function	Combines the passed Region with the current clipping region.
`ExtTextOut`	function	Draws an string without formatting (single line).
`ExtUTF8Out`	function
`FillRect`	function	Fills a rectangle by using the specified brush.
`FillRgn`	function	Fills a region using the specified brush.
`FindDefaultBrowser`	function	Gets the qualified path to the default browser application and its parameters.
`FloodFill`	function	Fills an area of the display surface with the current brush.
`FontIsMonoSpace`	function	Indicates whether the specified font handle represents a fixed-pitch typeface.
`Frame3d`	function
`FrameRect`	function	Draws a border around a rectangle.
`GetAcceleratorString`	function
`GetActiveWindow`	function	Returns the Handle of the active window of the calling thread.
`GetAvailableNativeCanvasTypes`	function
`GetAvailableNativeHandleTypes`	function
`GetBitmapBits`	function	Fills an buffer with the bitmap bits.
`GetBkColor`	function	Returns the background color of an device context.
`GetBValue`	function	Extracts the blue color value from a COLORREF.
`GetCapture`	function	Returns the window that captures mouse messages.
`GetCaretPos`	function	Returns the caret position, in client coordinates.
`GetCaretRespondToFocus`	function
`GetCharABCWidths`	function	Returns the ABC widths of an range of character codes.
`GetClientBounds`	function
`GetClientRect`	function	Returns the client rectangle of a control. Left and Top are always 0.
`GetClipBox`	function	Returns the smallest rectangle which includes the entire clipping region of an device context.
`GetClipRGN`	function	Returns the clipping region of an device context.
`GetCmdLineParamDescForInterface`	function
`GetCompositorExtendedBorder`	function	Gets extended border information added by the compositor for the Desktop Window Manager.
`GetControlConstraints`	function
`GetCurrentObject`	function	Returns an currently selected object in an device context.
`GetCursorPos`	function
`GetDC`	function	Returns the handle of an Device Context (DC) for the client area of a window.
`GetDCOpacity`	function
`GetDCOriginRelativeToWindow`	function
`GetDesignerDC`	function
`GetDeviceCaps`	function	Returns various device specific information.
`GetDeviceSize`	function
`GetDIBits`	function	Fill an buffer with the bitmap bits.
`GetDoubleClickTime`	function	Returns the double-click time, in milliseconds.
`GetDpiForMonitor`	function
`GetFocus`	function	Returns the handle of the window that has the focus in the current thread.
`GetFontLanguageInfo`	function	Returns language information about the currently selected font.
`GetForegroundWindow`	function	Returns the window that the user is currently working with, session wide.
`GetGValue`	function	Extracts the green color value from a COLORREF.
`GetIconInfo`	function	Returns information about an Icon or Cursor.
`GetKeyState`	function	The status of a virtual key.
`GetLCLOwnerObject`	function
`GetMapMode`	function	Returns the mapping mode of an device context.
`GetMonitorInfo`	function	Returns information about an display monitor.
`GetNativeCanvas`	function
`GetNativeHandle`	function
`GetObject`	function	Returns information about a graphics object.
`GetPaletteEntries`	function	Retrieves an range of color entries from a logical palette.
`GetParent`	function	Returns the parent window of a window.
`GetProp`	function	Retrieves an property value for a window.
`GetRGBIntValues`	procedure	Extracts the red, green and blue color values from a COLORREF.
`GetRGBValues`	procedure	Extracts the red, green and blue color values from a COLORREF.
`GetRgnBox`	function	Returns the bounding rectangle of a region, containing the entire region.
`GetROP2`	function	The current Foreground Mixing Mode in an device context.
`GetRValue`	function	Extracts the red color value from a COLORREF.
`GetScrollBarSize`	function
`GetScrollbarVisible`	function
`GetScrollInfo`	function	Returns all or selected information about a Scroll Bar.
`GetScrollPos`	function	Returns the scroll bar position.
`GetScrollRange`	function	Returns the minimum and maximum Position values of a Scroll Bar.
`GetStockObject`	function	Retrieves a handle to one of the predefined graphic objects.
`GetSysColor`	function	Retrieves the system color for standard display elements.
`GetSysColorBrush`	function	Retrieves a system brush for standard display elements.
`GetSystemMetrics`	function	Retrieves various system metrics.
`GetSystemPaletteEntries`	function	Retrieves an range of color entries from the system palette for a device.
`GetTextColor`	function	The current text color in an device context.
`GetTextExtentExPoint`	function	Calculates the number of characters, that fit into some horizontal space.
`GetTextExtentPoint`	function	Computes the display width and height of an string.
`GetTextExtentPoint32`	function	Computes the display width and height of an string.
`GetTextMetrics`	function	Retrieves the metrics for the currently selected font.
`GetTickCount`	function	Number of ticks (milliseconds) elapsed since the computer was started.
`GetTickCount64`	function	Number of ticks (milliseconds) elapsed since the computer was started.
`GetViewPortExtEx`	function	Returns the size of the viewport of an device context.
`GetViewPortOrgEx`	function	Returns the origin of the viewport of an device context.
`GetWindowExtEx`	function	Returns the extent of a window, in logical units.
`GetWindowLong`	function	Returns attributes for the specified window handle.
`GetWindowOrgEx`	function	Retrieves the window origin of an device context, in logical units.
`GetWindowRect`	function	Retrieves the bounding rectangle for a window, including the window decoration in screen coordinates.
`GetWindowRelativePosition`	function
`GetWindowSize`	function	Returns the Width and Height of a window, including the window decoration.
`GradientFill`	function	Fills rectangle or triangle areas with gradient colors.
`HideCaret`	function	Removes the caret from the screen.
`IndexToOverlayMask`	function	Converts an imagelist index into an overlay index.
`InflateRect`	function	Inflates the rectangle in all directions.
`InitializeCriticalSection`	procedure	Initializes a Critical Section object.
`IntersectClipRect`	function	Shrinks the clipping region of an Device Context to a rectangular boundary, e.g. a text area.
`IntersectRect`	function	Intersects SrcRect1 and SrcRect2 into DestRect.
`InvalidateFrame`	function
`InvalidateRect`	function	Marks a display area for repaint.
`InvalidateRgn`	function	Marks a display area for repaint.
`IsCDIntfControl`	function
`IsCharAlphaNumeric`	function	Checks for ASCII letter or digit characters.
`IsDBCSLeadByte`	function
`IsDesignerDC`	function
`IsIconic`	function	True when the window is minimized.
`IsMobilePlatform`	function
`IsRectEmpty`	function	Returns True if the rectangle is empty.
`IsWindow`	function	Checks whether a handle refers to a window.
`IsWindowEnabled`	function	Determines whether a window can receive mouse and keyboard input.
`IsWindowVisible`	function	The definite Visible state of a window.
`IsZoomed`	function	True when the window is maximized.
`KillTimer`	function	Removes an timer.
`LeaveCriticalSection`	procedure	Releases a critical section, for use by other threads.
`LineTo`	function	Draws a line from the current position up to, but not including, the specified point.
`LoadBitmap`	function
`LoadCursor`	function
`LoadIcon`	function
`LParamExtractLoHiWord`	procedure	Converts an Integer parameter value into low-order and high-order Word values.
`LParamHiWord`	function	Gets the high-order Word value stored in the specified Integer pointer.
`LParamLoWord`	function	Gets the low-order Word value stored in the specified Integer pointer.
`LPtoDP`	function	Converts logical coordinates into device coordinates.
`MakeLong`	function	Copies two words into a double word.
`MakeLParam`	function	Copies two words into a double word, usable as a message lParam.
`MakeLResult`	function	Copies two words into a double word, usable as a message Result.
`MakeROP4`	function
`MakeWord`	function	Copies two bytes into a word.
`MakeWParam`	function	Copies two words into a double word, usable as a message wParam.
`MaskBlt`	function	Copies part of an source DC into an destination DC, using the specified foreground and background raster operations.
`MessageBox`	function	Displays a modal dialog with the given text, caption, icon and buttons.
`MonitorFromPoint`	function	Finds an monitor from screen coordinates.
`MonitorFromRect`	function
`MonitorFromWindow`	function	Finds the monitor which contains most of the specified window.
`MoveToEx`	function	Moves the current position to the specified point.
`MoveWindowOrgEx`	function
`MsgKeyDataToShiftState`	function
`NotifyUser`	procedure
`NotifyUserAtXY`	procedure
`OffsetRgn`	function	Moves a region by the specified relative offset.
`OpenDocument`	function	Opens the document using the default application associated with the specified file.
`OpenURL`	function	Opens a given URL with the default browser for the system.
`PaintRgn`	function
`PeekMessage`	function
`Pie`	function	Draws a filled pie-shaped wedge, from an ellipse and two radials.
`PointToSmallPoint`	function
`PointToSmallPointNoChecks`	function
`PolyBezier`	function	Draws Bézier curves.
`Polygon`	function	Draws a Polygon.
`Polyline`	function	Draws a sequence of lines.
`PostMessage`	function	Sends a message to a window.
`PredefinedClipboardFormat`	function
`PromptUser`	function
`PromptUserAtXY`	function
`PtInRect`	function	Checks whether a Point is within a Rect.
`PtInRegion`	function	Determines whether the specified coordinates are within the given region handle.
`RadialArc`	function
`RadialChord`	function
`RadialPie`	function
`RawImage_CreateBitmaps`	function
`RawImage_DescriptionFromBitmap`	function
`RawImage_DescriptionFromDevice`	function
`RawImage_FromBitmap`	function
`RawImage_FromDevice`	function
`RawImage_QueryDescription`	function
`RealizePalette`	function
`Rectangle`	function
`RectInRegion`	function
`RectVisible`	function	Indicates whether the specified rectangle in visible in the clipping region for the device context.
`RedrawWindow`	function	Redraws (part of) a window.
`RegroupMenuItem`	function
`ReleaseCapture`	function	Restores normal mouse input processing, after .
`ReleaseDC`	function	Releases an Device Context obtained by GetDC.
`ReleaseDesignerDC`	function
`RemoveEventHandler`	procedure
`RemovePipeEventHandler`	procedure
`RemoveProcessEventHandler`	procedure
`RemoveProp`	function	Removes a named property from a window.
`RequestInput`	function
`RestoreDC`	function	Restores a Device Context (DC) to an previously saved state.
`RGB`	function	Combines Red, Green and Blue values into an TColorRef value.
`RoundRect`	function	Draws a rectangle with rounded corners to the specified device context.
`SaveDC`	function	Saves the state of a Device Context in the context stack.
`ScreenToClient`	function	Converts absolute Screen coordinates into Client relative coordinates.
`ScrollWindow`	function	Scrolls the content of a window, by a number of pixels.
`ScrollWindowEx`	function
`SelectClipRGN`	function	Sets the ClipRegion of an DeviceContext.
`SelectInFolder`	function	Opens a system file manager, displays a directory, and optionally selects the given file.
`SelectObject`	function	Selects an object into an device context.
`SelectPalette`	function
`SendCachedLCLMessages`	procedure
`SendMessage`	function	Sends a message directed to a specific window to the message pool for the application.
`SetActiveWindow`	function	Sets focus to the specified window, if the application is on top.
`SetBkColor`	function	Sets the current background color of an device context.
`SetBkMode`	function	Sets the background mix mode (transparency) of an device context.
`SetCanvasScaleFactor`	procedure
`SetCapture`	function	Sets the mouse capture to the specified window.
`SetCaretPos`	function	Moves the Caret to the specified coordinates.
`SetCaretPosEx`	function	Moves the Caret into a window.
`SetCaretRespondToFocus`	function
`SetComboMinDropDownSize`	function
`SetCursor`	function	Changes the shape of the mouse cursor.
`SetCursorPos`	function	Changes the position of the mouse cursor.
`SetDCOpacity`	procedure
`SetEventHandlerFlags`	procedure
`SetFocus`	function	Sets the keyboard input focus to the specified window handle.
`SetForegroundWindow`	function	Moves a window in front of all other windows, and activates it.
`SetMapMode`	function	Sets the mapping mode of an device context.
`SetMenu`	function	Assigns a menu to a window.
`SetParent`	function	Changes the parent of a window.
`SetProp`	function	Adds a property to a window.
`SetRect`	function	Copies coordinates into a rectangle.
`SetRectEmpty`	function	Clears the rectangle to all zero coordinates.
`SetRectRgn`	function
`SetROP2`	function	Sets the Foreground Mixing Mode in an device context.
`SetRubberBandRect`	procedure
`SetScrollInfo`	function
`SetScrollPos`	function	Changes the Position of an Scroll Bar slider.
`SetScrollRange`	function	Sets the minimum and maximum position values for a scroll bar.
`SetStretchBltMode`	function	Sets the StrechBlt mode for an device context.
`SetSysColors`	function	Sets the colors for one or more display elements of window borders and desktop.
`SetTextCharacterExtra`	function	Sets extra inter-character spacing in text output.
`SetTextColor`	function	Sets the text color on a device context.
`SetTimer`	function	Creates or resets an timer for the given time interval.
`SetViewPortExtEx`	function	Sets the extent of the viewport for a device context.
`SetViewPortOrgEx`	function	Sets the device origin corresponding to the window origin (0,0) in an device context.
`SetWindowExtEx`	function	Sets the extent of the window for an device context.
`SetWindowLong`	function	Sets an attribute of a window.
`SetWindowOrgEx`	function	Specifies which window point maps to the viewport origin (0,0).
`SetWindowPos`	function	Changes the size, position, and Z order of a window.
`SetWindowRgn`	function	Defines the visible region of a window or control.
`ShowCaret`	function	Shows the Caret (text cursor).
`ShowScrollBar`	function	Shows or hides a Scroll Bar.
`ShowSelectItemDialog`	function
`ShowWindow`	function	Shows a window in an specific state.
`SmallPointToPoint`	function	Converts a TSmallPoint value to a TPoint value.
`StretchBlt`	function	Copies a rectangular region into an device context, shrinking or stretching it as required.
`StretchDIBits`	function	Copies a rectangular region from a DIB into an device context, shrinking or stretching it as required.
`StretchMaskBlt`	function
`SubtractRect`	function	Computes the bounding box with the geometric difference between two rectangles.
`SystemParametersInfo`	function	Retrieves or sets one of the system-wide parameters.
`TextOut`	function	Draws an string without formatting (single line).
`TextUTF8Out`	function
`UnionRect`	function	Computes the bounding box of the union of two rectangles.
`UpdateWindow`	function	Forces an immediate repaint of a window, if required.
`WindowFromPoint`	function	Finds the window containing the specified point.

Types

TOpenParamStringProc procedure type

Variables

`OnListViewDialogResult`	variable
`OnShowSelectItemDialogResult`	variable
`OpenDocumentWidgetsetImplementation`	variable
`OpenURLWidgetsetImplementation`	variable

Uses

An experiment, built from Lazarus main 2dfa93c66e of 10-22-2026. Not the official Lazarus documentation.