Hi all,
the objective of this patch is to create an easy and efficient way to
have scrollbars in custom-controls.
For this purpose it makes TScrollingWinControl inherit from
TCustomControl and moves/separates the routine which 'compute' the
scrollbars' attributes according to the control's internal state to
the control itself.
I tried to avoid any unnecessary change in this patch, but IMHO
there's no use for any virtual methods in TControlScrollbar and for
TControlScrollbar.FControl being TWinControl instead of TScrollingWC,
and I'd change these...
Cheers,
Flavio
(dang, it seems KDE in edgy currently breaks with utf-8 locales :-(
------------ director's cut ---------------- ;-)
this is my try at making TScrollingWinControl more useful, in
particular useful at slimming the main unit from SynEdit ;-)
It always annoyed me that in the SynEdit project we had to write
different code to setup scrollbars in Win32 and CLX and that
TScrollingWinControl doesn't help us there a single bit. And we needed
help: in Win32 we use API calls; in CLX we use two TScrollBar and some
hacks all-around the code :-/
Index: forms.pp
===================================================================
--- forms.pp (revision 9763)
+++ forms.pp (working copy)
@@ -104,7 +104,6 @@
function VisibleIsStored: boolean; virtual;
procedure AutoCalcRange; virtual;
procedure ControlUpdateScrollBars; virtual;
- procedure ScrollControlBy(DeltaX, DeltaY: integer); virtual;
procedure ScrollHandler(var Message: TLMScroll);
procedure SetIncrement(const AValue: TScrollBarInc); virtual;
procedure SetPage(const AValue: TScrollBarInc); virtual;
@@ -113,7 +112,6 @@
procedure SetSize(const AValue: integer); virtual;
procedure SetSmooth(const Value: Boolean); virtual;
procedure SetVisible(const Value: Boolean); virtual;
- Procedure UpdateScrollBar; virtual;
public
constructor Create(AControl: TWinControl; AKind: TScrollBarKind);
procedure Assign(Source: TPersistent); override;
@@ -123,6 +121,7 @@
function GetOtherScrollBar: TControlScrollBar;
function GetHorzScrollBar: TControlScrollBar; virtual;
function GetVertScrollBar: TControlScrollBar; virtual;
+ procedure UpdateScrollBar; virtual;
property Size: integer read GetSize write SetSize stored false;
published
property Increment: TScrollBarInc read GetIncrement write SetIncrement default 8;
@@ -136,38 +135,32 @@
{ TScrollingWinControl }
- TScrollingWinControl = class(TWinControl)
+ TScrollingWinControl = class(TCustomControl)
private
FHorzScrollBar: TControlScrollBar;
FVertScrollBar: TControlScrollBar;
FAutoScroll: Boolean;
- FOnPaint: TNotifyEvent;
- FCanvas: TControlCanvas;
FIsUpdating: Boolean;
procedure SetAutoScroll(Value: Boolean);
procedure SetHorzScrollBar(Value: TControlScrollBar);
procedure SetVertScrollBar(Value: TControlScrollBar);
+ //todo: rename to IsScrollbarsStored
Function StoreScrollBars : Boolean;
protected
procedure AlignControls(AControl: TControl; var ARect: TRect); override;
procedure CreateWnd; override;
function GetClientScrollOffset: TPoint; override;
- Procedure WMEraseBkgnd(var Message: TLMEraseBkgnd); message LM_ERASEBKGND;
- procedure WMPaint(var message: TLMPaint); message LM_PAINT;
procedure DoOnResize; override;
procedure WMHScroll(var Message : TLMHScroll); message LM_HScroll;
procedure WMVScroll(var Message : TLMVScroll); message LM_VScroll;
procedure ScrollBy(DeltaX, DeltaY: Integer);
- property OnPaint: TNotifyEvent read FOnPaint write FOnPaint;
+ procedure ComputeScrollbars; virtual;
+ procedure ScrollbarHandler(p_ScrollKind: TScrollBarKind; p_OldPosition: Integer); virtual;
public
Constructor Create(AOwner : TComponent); Override;
Destructor Destroy; Override;
- procedure Paint; dynamic;
- procedure PaintWindow(dc : Hdc); override;
- procedure UpdateScrollbars; virtual;
+ procedure UpdateScrollbars;
function HasVisibleScrollbars: boolean; virtual;
- procedure DestroyWnd; override;
- property Canvas: TControlCanvas read FCanvas;
published
property AutoScroll: Boolean read FAutoScroll write SetAutoScroll;
property HorzScrollBar: TControlScrollBar
Index: include/controlscrollbar.inc
===================================================================
--- include/controlscrollbar.inc (revision 9763)
+++ include/controlscrollbar.inc (working copy)
@@ -47,10 +47,8 @@
// scroll content of FControl
OldPosition:=FPosition;
FPosition := Value;
- if Kind = sbVertical then
- ScrollControlBy(0, OldPosition - FPosition)
- else
- ScrollControlBy(OldPosition - FPosition, 0);
+ if FControl is TScrollingWinControl then
+ TScrollingWinControl(FControl).ScrollbarHandler(Kind, OldPosition);
// check that the new position is also set on the scrollbar
if HandleAllocated
@@ -169,12 +167,6 @@
ControlUpdateScrollBars;
end;
-procedure TControlScrollBar.ScrollControlBy(DeltaX, DeltaY: integer);
-begin
- if FControl is TScrollingWinControl then
- TScrollingWinControl(FControl).ScrollBy(DeltaX, DeltaY);
-end;
-
procedure TControlScrollBar.SetSmooth(const Value: Boolean);
begin
// only used by the ScrollHandler procedure
@@ -237,58 +229,19 @@
procedure TControlScrollBar.UpdateScrollBar;
var
ScrollInfo: TScrollInfo;
- SBSize : Longint;
- OtherScrollbar: TControlScrollBar;
- CurMax: Integer;
begin
+ //todo: probably needs to be moved somewhere else.
FAutoRange := 0;
if FControl is TScrollingWinControl then begin
ScrollInfo.cbSize := SizeOf(ScrollInfo);
ScrollInfo.fMask := SIF_ALL;
ScrollInfo.nMin := 0;
+ ScrollInfo.nMax := FRange;
ScrollInfo.nPos := FPosition;
ScrollInfo.nTrackPos := FPosition;
-
- With TScrollingWinControl(FControl) do begin
- // page
- if Self.Kind=sbVertical then
- FPage := TScrollBarInc(Min(ClientHeight - 1,High(FPage)))
- else
- FPage := TScrollBarInc(Min(ClientWidth - 1,High(FPage)));
- ScrollInfo.nPage := FPage;
-
- // range
- OtherScrollbar:=GetOtherScrollBar;
- If OtherScrollbar.FVisible then
- SBSize := OtherScrollbar.Size
- else
- SBSize := 0;
- if Kind=sbVertical then begin
- SBSize:=ClientHeight - SBSize;
- end else begin
- SBSize:=ClientWidth - SBSize;
- end;
- if (fRange>SBSize) and (SBSize>0) then FAutoRange := (FRange - SBSize)
- else FAutoRange := 0;
- ScrollInfo.nMax := FRange;
-
- // visible
- if Kind=sbVertical then
- CurMax:=Height
- else
- CurMax:=Width;
- If (Self.FVisible and not FAutoScroll)
- or (FAutoScroll and (ScrollInfo.nMax > 0) and (ScrollInfo.nMax > CurMax))
- then
- Self.FVisible := True
- else
- Self.FVisible := False;
-
- // transmit scollinfo to interface
- if HandleAllocated then
- SetScrollInfo(Handle, IntfBarKind[Kind], ScrollInfo, Self.FVisible);
- end
+ if HandleAllocated then
+ SetScrollInfo(FControl.Handle, IntfBarKind[Kind], ScrollInfo, FVisible);
end;
SetPosition(ScrollInfo.nTrackPos);
Index: include/customform.inc
===================================================================
--- include/customform.inc (revision 9763)
+++ include/customform.inc (working copy)
@@ -760,12 +760,12 @@
begin
// FCanvas.Lock;
try
- FCanvas.Handle := DC;
+ Canvas.Handle := DC;
//DebugLn('[TCustomForm.PaintWindow] ',ClassName,' DC=',DbgS(DC,8),' ',DbgS(FCanvas.Handle,8));
try
if FDesigner <> nil then FDesigner.PaintGrid else Paint;
finally
- FCanvas.Handle := 0;
+ Canvas.Handle := 0;
end;
finally
// FCanvas.Unlock;
Index: include/scrollingwincontrol.inc
===================================================================
--- include/scrollingwincontrol.inc (revision 9763)
+++ include/scrollingwincontrol.inc (working copy)
@@ -56,42 +56,6 @@
inherited AlignControls(AControl, ARect);
end;
-Procedure TScrollingWinControl.WMEraseBkgnd(var Message: TLMEraseBkgnd);
-begin
- inherited WMEraseBkgnd(Message);
-end;
-
-procedure TScrollingWinControl.WMPaint(var Message: TLMPaint);
-begin
- Include(FControlState, csCustomPaint);
- try
- inherited WMPaint(Message);
- finally
- Exclude(FControlState, csCustomPaint);
- end;
-end;
-
-Procedure TScrollingWinControl.Paint;
-begin
- if Assigned (FOnPaint) then
- FOnPaint(Self);
-end;
-
-Procedure TScrollingWinControl.PaintWindow(DC : Hdc);
-begin
- FCanvas.Lock;
- try
- FCanvas.Handle := DC;
- try
- Paint;
- finally
- FCanvas.Handle := 0;
- end;
- finally
- FCanvas.Unlock;
- end;
-end;
-
procedure TScrollingWinControl.DoOnResize;
begin
inherited DoOnResize;
@@ -110,11 +74,64 @@
FVertScrollbar.Assign(Value);
end;
+procedure TScrollingWinControl.ComputeScrollbars;
+
+ procedure UpdateRange(p_Bar: TControlScrollBar);
+ var
+ SBSize: Longint;
+ OtherScrollbar: TControlScrollBar;
+ begin
+ p_Bar.FAutoRange := 0;
+ OtherScrollbar := p_Bar.GetOtherScrollBar;
+ If OtherScrollbar.FVisible then
+ SBSize := OtherScrollbar.Size
+ else
+ SBSize := 0;
+ if p_Bar.Kind = sbVertical then
+ SBSize := ClientHeight - SBSize
+ else
+ SBSize := ClientWidth - SBSize;
+ if (p_Bar.fRange>SBSize) and (SBSize>0) then
+ p_Bar.FAutoRange := (p_Bar.FRange - SBSize)
+ else
+ p_Bar.FAutoRange := 0;
+ end;
+
+ procedure UpdateVisible(p_Bar: TControlScrollBar);
+ var
+ CurMax: Integer;
+ begin
+ if p_Bar.Kind = sbVertical then
+ CurMax := Height
+ else
+ CurMax := Width;
+ If (p_Bar.FVisible and not FAutoScroll)
+ or (FAutoScroll and (p_Bar.FRange > 0) and (p_Bar.FRange > CurMax))
+ then
+ p_Bar.FVisible := True
+ else
+ p_Bar.FVisible := False;
+ end;
+
+begin
+ //todo: why doesn't it simply use ClientWidth/Height?
+ // page
+ HorzScrollbar.FPage := Min(ClientWidth -1, High(HorzScrollbar.FPage));
+ VertScrollbar.FPage := Min(ClientHeight -1, High(VertScrollbar.FPage));
+ // range
+ UpdateRange(VertScrollbar);
+ UpdateRange(VertScrollbar);
+ // visible
+ UpdateVisible(HorzScrollbar);
+ UpdateVisible(VertScrollbar);
+end;
+
Procedure TScrollingWinControl.UpdateScrollbars;
begin
If FIsUpdating then exit;
FIsUpdating := True;
try
+ ComputeScrollbars;
FVertScrollbar.UpdateScrollbar;
FHorzScrollbar.UpdateScrollbar;
finally
@@ -128,13 +145,6 @@
and (HorzScrollBar<>nil) and HorzScrollBar.Visible;
end;
-procedure TScrollingWinControl.DestroyWnd;
-begin
- inherited DestroyWnd;
- if Canvas<>nil then
- Canvas.FreeHandle;
-end;
-
Function TScrollingWinControl.StoreScrollBars : Boolean;
begin
Result := Not AutoScroll;
@@ -144,10 +154,19 @@
begin
if HandleAllocated then begin
TWSScrollingWinControlClass(WidgetSetClass).ScrollBy(Self, DeltaX, DeltaY);
+ //todo: shouldn't call Invalidate. Instead, the TWidgetSet should call it if it needs to.
Invalidate;
end;
end;
+procedure TScrollingWinControl.ScrollbarHandler(p_ScrollKind: TScrollBarKind; p_OldPosition: Integer);
+begin
+ if p_ScrollKind = sbVertical then
+ ScrollBy(0, FVertScrollBar.Position - p_OldPosition)
+ else
+ ScrollBy(FHorzScrollBar.Position - p_OldPosition, 0);
+end;
+
Procedure TScrollingWinControl.WMVScroll(var Message : TLMVScroll);
begin
VertScrollbar.ScrollHandler(Message);
@@ -162,9 +181,6 @@
begin
Inherited Create(AOwner);
- FCanvas := TControlCanvas.Create;
- FCanvas.Control := Self;
-
FVertScrollbar := TControlScrollBar.Create(Self, sbVertical);
FHorzScrollbar := TControlScrollBar.Create(Self, sbHorizontal);
@@ -177,7 +193,6 @@
begin
FreeThenNil(FHorzScrollBar);
FreeThenNil(FVertScrollBar);
- FreeThenNil(FCanvas);
inherited Destroy;
end;
