I\'m trying to figure out how I can make a custom control in a way where user can scroll in all directions, but with a fixed row and column. A grid is not suitable for what
The easiest way is to make a control without scrollbars and then put scrollbars over it with fine control of their size and position.
With Delphi 3-5 you could then encapsulate it as your new control using Custom Containers Pack, and drop onto new forms just like u do with regular grid.
Since D5 CCP is no more available but limited analogue is given as VCL TFrame. OR you can create those scrollbars in runtime - you need to search for Windows Handle creating routine, (trace TControl.Handle getter method), that might be ReCreateWnd or such, and as GDI handle created - create your scroll-bars over it.
First, I thought you could do with this component (sample image) which is capable of holding controls in cells, but from your comment I understand that you want to draw everything yourself. So I wrote a 'THeaderGrid
' component:
procedure TForm1.FormCreate(Sender: TObject);
begin
with THeaderGrid.Create(Self) do
begin
Align := alClient;
OnDrawCell := DrawCell;
OnDrawColHeader := DrawCell;
OnDrawRowHeader := DrawCell;
Parent := Self;
end;
end;
procedure TForm1.DrawCell(Sender: TObject; ACanvas: TCanvas; ACol,
ARow: Integer; R: TRect);
begin
ACanvas.TextOut(R.Left + 2, R.Top + 2, Format('(%d,%d)', [ACol, ARow]));
end;
The component is build up out of three TPaintScroller
controls (a TPaintBox
on a TScrollBox
). Actually, for both headers, TScrollBox
is a little bit heavyweighted, but it was kind of handy to use the same control as for the data region with the cells.
There are three OnDraw events, one for both headers and one for the cells, but you could all set them to the same handler, alike the example above. Distinguish each by the column or row index being -1
.
unit HeaderGrid;
interface
uses
Classes, Controls, Windows, Messages, Graphics, Forms, ExtCtrls, StdCtrls;
type
TPaintEvent = procedure(ACanvas: TCanvas) of object;
TPaintScroller = class(TScrollingWinControl)
private
FOnPaint: TPaintEvent;
FOnScroll: TNotifyEvent;
FPainter: TPaintBox;
function GetPaintHeight: Integer;
function GetPaintWidth: Integer;
function GetScrollBars: TScrollStyle;
procedure SetPaintHeight(Value: Integer);
procedure SetPaintWidth(Value: Integer);
procedure SetScrollBars(Value: TScrollStyle);
procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
procedure WMHScroll(var Message: TWMScroll); message WM_HSCROLL;
procedure WMVScroll(var Message: TWMScroll); message WM_VSCROLL;
protected
procedure CreateParams(var Params: TCreateParams); override;
function DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
MousePos: TPoint): Boolean; override;
procedure DoPaint(Sender: TObject); virtual;
procedure DoScroll; virtual;
procedure PaintWindow(DC: HDC); override;
procedure Resize; override;
public
constructor Create(AOwner: TComponent); override;
published
property OnPaint: TPaintEvent read FOnPaint write FOnPaint;
property OnScroll: TNotifyEvent read FOnScroll write FOnScroll;
property PaintHeight: Integer read GetPaintHeight write SetPaintHeight;
property PaintWidth: Integer read GetPaintWidth write SetPaintWidth;
property ScrollBars: TScrollStyle read GetScrollBars write SetScrollBars
default ssBoth;
end;
TDrawCellEvent = procedure(Sender: TObject; ACanvas: TCanvas; ACol,
ARow: Integer; R: TRect) of object;
THeaderGrid = class(TCustomControl)
private
FCellScroller: TPaintScroller;
FColCount: Integer;
FColHeader: TPaintScroller;
FColWidth: Integer;
FOnDrawCell: TDrawCellEvent;
FOnDrawColHeader: TDrawCellEvent;
FOnDrawRowHeader: TDrawCellEvent;
FRowCount: Integer;
FRowHeader: TPaintScroller;
FRowHeight: Integer;
procedure CellsScrolled(Sender: TObject);
function GetColHeaderHeight: Integer;
function GetRowHeaderWidth: Integer;
procedure PaintCells(ACanvas: TCanvas);
procedure PaintColHeader(ACanvas: TCanvas);
procedure PaintRowHeader(ACanvas: TCanvas);
procedure SetColCount(Value: Integer);
procedure SetColHeaderHeight(Value: Integer);
procedure SetColWidth(Value: Integer);
procedure SetRowCount(Value: Integer);
procedure SetRowHeaderWidth(Value: Integer);
procedure SetRowHeight(Value: Integer);
procedure UpdateSize;
procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
protected
procedure CreateParams(var Params: TCreateParams); override;
procedure DoDrawCell(ACanvas: TCanvas; ACol, ARow: Integer;
R: TRect); virtual;
procedure DoDrawColHeader(ACanvas: TCanvas; ACol: Integer;
R: TRect); virtual;
procedure DoDrawRowHeader(ACanvas: TCanvas; ARow: Integer;
R: TRect); virtual;
procedure Paint; override;
public
constructor Create(AOwner: TComponent); override;
procedure MouseWheelHandler(var Message: TMessage); override;
published
property ColCount: Integer read FColCount write SetColCount default 5;
property ColHeaderHeight: Integer read GetColHeaderHeight
write SetColHeaderHeight default 24;
property ColWidth: Integer read FColWidth write SetColWidth default 64;
property OnDrawCell: TDrawCellEvent read FOnDrawCell write FOnDrawCell;
property OnDrawColHeader: TDrawCellEvent read FOnDrawColHeader
write FOnDrawColHeader;
property OnDrawRowHeader: TDrawCellEvent read FOnDrawRowHeader
write FOnDrawRowHeader;
property RowCount: Integer read FRowCount write SetRowCount default 5;
property RowHeaderWidth: Integer read GetRowHeaderWidth
write SetRowHeaderWidth default 64;
property RowHeight: Integer read FRowHeight write SetRowHeight default 24;
published
property Color;
property Font;
property ParentColor default False;
property TabStop default True;
end;
implementation
{ TPaintScroller }
constructor TPaintScroller.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
ControlStyle := [csOpaque];
HorzScrollBar.Tracking := True;
VertScrollBar.Tracking := True;
Width := 100;
Height := 100;
FPainter := TPaintBox.Create(Self);
FPainter.SetBounds(0, 0, 100, 100);
FPainter.OnPaint := DoPaint;
FPainter.Parent := Self;
end;
procedure TPaintScroller.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params.WindowClass do
Style := Style and not (CS_HREDRAW or CS_VREDRAW);
end;
function TPaintScroller.DoMouseWheel(Shift: TShiftState;
WheelDelta: Integer; MousePos: TPoint): Boolean;
begin
VertScrollBar.Position := VertScrollBar.Position - WheelDelta;
DoScroll;
Result := True;
end;
procedure TPaintScroller.DoPaint(Sender: TObject);
begin
if Assigned(FOnPaint) then
FOnPaint(FPainter.Canvas);
end;
procedure TPaintScroller.DoScroll;
begin
if Assigned(FOnScroll) then
FOnScroll(Self);
end;
function TPaintScroller.GetPaintHeight: Integer;
begin
Result := FPainter.Height;
end;
function TPaintScroller.GetPaintWidth: Integer;
begin
Result := FPainter.Width;
end;
function TPaintScroller.GetScrollBars: TScrollStyle;
begin
if HorzScrollBar.Visible and VertScrollBar.Visible then
Result := ssBoth
else if not HorzScrollBar.Visible and VertScrollBar.Visible then
Result := ssVertical
else if HorzScrollBar.Visible and not VertScrollBar.Visible then
Result := ssHorizontal
else
Result := ssNone;
end;
procedure TPaintScroller.PaintWindow(DC: HDC);
begin
with FPainter do
ExcludeClipRect(DC, 0, 0, Width + Left, Height + Top);
FillRect(DC, ClientRect, Brush.Handle);
end;
procedure TPaintScroller.Resize;
begin
DoScroll;
inherited Resize;
end;
procedure TPaintScroller.SetPaintHeight(Value: Integer);
begin
FPainter.Height := Value;
end;
procedure TPaintScroller.SetPaintWidth(Value: Integer);
begin
FPainter.Width := Value;
end;
procedure TPaintScroller.SetScrollBars(Value: TScrollStyle);
begin
HorzScrollBar.Visible := (Value = ssBoth) or (Value = ssHorizontal);
VertScrollBar.Visible := (Value = ssBoth) or (Value = ssVertical);
end;
procedure TPaintScroller.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
Message.Result := 1;
end;
procedure TPaintScroller.WMHScroll(var Message: TWMScroll);
begin
inherited;
DoScroll;
end;
procedure TPaintScroller.WMVScroll(var Message: TWMScroll);
begin
inherited;
DoScroll;
end;
{ THeaderGrid }
procedure THeaderGrid.CellsScrolled(Sender: TObject);
begin
FColHeader.FPainter.Left := -FCellScroller.HorzScrollBar.Position;
FRowHeader.FPainter.Top := -FCellScroller.VertScrollBar.Position;
end;
constructor THeaderGrid.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
ControlStyle := [csOpaque];
ParentColor := False;
TabStop := True;
FCellScroller := TPaintScroller.Create(Self);
FCellScroller.Anchors := [akLeft, akTop, akRight, akBottom];
FCellScroller.OnPaint := PaintCells;
FCellScroller.OnScroll := CellsScrolled;
FCellScroller.AutoScroll := True;
FCellScroller.Parent := Self;
FColHeader := TPaintScroller.Create(Self);
FColHeader.Anchors := [akLeft, akTop, akRight];
FColHeader.OnPaint := PaintColHeader;
FColHeader.ScrollBars := ssNone;
FColHeader.Parent := Self;
FRowHeader := TPaintScroller.Create(Self);
FRowHeader.Anchors := [akLeft, akTop, akBottom];
FRowHeader.OnPaint := PaintRowHeader;
FRowHeader.ScrollBars := ssNone;
FRowHeader.Parent := Self;
Width := 320;
Height := 120;
ColCount := 5;
RowCount := 5;
ColWidth := 64;
RowHeight := 24;
ColHeaderHeight := 24;
RowHeaderWidth := 64;
end;
procedure THeaderGrid.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params.WindowClass do
Style := Style and not (CS_HREDRAW or CS_VREDRAW);
end;
procedure THeaderGrid.DoDrawCell(ACanvas: TCanvas; ACol, ARow: Integer;
R: TRect);
begin
if Assigned(FOnDrawCell) then
FOnDrawCell(Self, ACanvas, ACol, ARow, R);
end;
procedure THeaderGrid.DoDrawColHeader(ACanvas: TCanvas; ACol: Integer;
R: TRect);
begin
if Assigned(FOnDrawColHeader) then
FOnDrawColHeader(Self, ACanvas, ACol, -1, R);
end;
procedure THeaderGrid.DoDrawRowHeader(ACanvas: TCanvas; ARow: Integer;
R: TRect);
begin
if Assigned(FOnDrawRowHeader) then
FOnDrawRowHeader(Self, ACanvas, -1, ARow, R);
end;
function THeaderGrid.GetColHeaderHeight: Integer;
begin
Result := FColHeader.Height;
end;
function THeaderGrid.GetRowHeaderWidth: Integer;
begin
Result := FRowHeader.Width;
end;
procedure THeaderGrid.MouseWheelHandler(var Message: TMessage);
begin
with Message do
Result := FCellScroller.Perform(CM_MOUSEWHEEL, WParam, LParam);
if Message.Result = 0 then
inherited MouseWheelHandler(Message);
end;
procedure THeaderGrid.Paint;
var
R: TRect;
begin
Canvas.Brush.Color := Color;
R := Rect(0, 0, RowHeaderWidth, ColHeaderHeight);
if IntersectRect(R, R, Canvas.ClipRect) then
Canvas.FillRect(R);
Canvas.Brush.Color := clBlack;
R := Rect(0, ColHeaderHeight, Width, ColHeaderHeight + 1);
if IntersectRect(R, R, Canvas.ClipRect) then
Canvas.FillRect(R);
R := Rect(RowHeaderWidth, 0, RowHeaderWidth + 1, Height);
if IntersectRect(R, R, Canvas.ClipRect) then
Canvas.FillRect(R);
end;
procedure THeaderGrid.PaintCells(ACanvas: TCanvas);
var
Col: Integer;
Row: Integer;
R: TRect;
Dummy: TRect;
begin
ACanvas.Brush.Color := Color;
ACanvas.Font := Font;
ACanvas.FillRect(ACanvas.ClipRect);
for Row := 0 to FRowCount - 1 do
begin
R := Bounds(0, Row * FRowHeight, FColWidth, FRowHeight);
for Col := 0 to FColCount - 1 do
begin
if IntersectRect(Dummy, R, ACanvas.ClipRect) then
begin
DoDrawCell(ACanvas, Col, Row, R);
if ACanvas.Pen.Style <> psSolid then
ACanvas.Pen.Style := psSolid;
if ACanvas.Pen.Color <> clSilver then
ACanvas.Pen.Color := clSilver;
ACanvas.MoveTo(R.Left, R.Bottom - 1);
ACanvas.LineTo(R.Right - 1, R.Bottom - 1);
ACanvas.LineTo(R.Right - 1, R.Top - 1);
end;
OffsetRect(R, FColWidth, 0);
end;
end;
end;
procedure THeaderGrid.PaintColHeader(ACanvas: TCanvas);
var
Col: Integer;
R: TRect;
Dummy: TRect;
begin
ACanvas.Brush.Color := Color;
ACanvas.Font := Font;
ACanvas.FillRect(ACanvas.ClipRect);
R := Rect(0, 0, FColWidth, ColHeaderHeight);
for Col := 0 to FColCount - 1 do
begin
if IntersectRect(Dummy, R, ACanvas.ClipRect) then
DoDrawColHeader(ACanvas, Col, R);
OffsetRect(R, FColWidth, 0);
end;
end;
procedure THeaderGrid.PaintRowHeader(ACanvas: TCanvas);
var
Row: Integer;
R: TRect;
Dummy: TRect;
begin
ACanvas.Brush.Color := Color;
ACanvas.Font := Font;
ACanvas.FillRect(ACanvas.ClipRect);
R := Rect(0, 0, RowHeaderWidth, FRowHeight);
for Row := 0 to FRowCount - 1 do
begin
if IntersectRect(Dummy, R, ACanvas.ClipRect) then
begin
DoDrawRowHeader(ACanvas, Row, R);
if ACanvas.Pen.Style <> psSolid then
ACanvas.Pen.Style := psSolid;
if ACanvas.Pen.Color <> clSilver then
ACanvas.Pen.Color := clSilver;
ACanvas.MoveTo(R.Left, R.Bottom - 1);
ACanvas.LineTo(R.Right - 1, R.Bottom - 1);
end;
OffsetRect(R, 0, FRowHeight);
end;
end;
procedure THeaderGrid.SetColCount(Value: Integer);
begin
if FColCount <> Value then
begin
FColCount := Value;
UpdateSize;
end;
end;
procedure THeaderGrid.SetColHeaderHeight(Value: Integer);
begin
if Value >= 0 then
begin
FColHeader.Height := Value;
FRowHeader.BoundsRect := Rect(0, Value + 1, RowHeaderWidth, Height);
FCellScroller.BoundsRect := Rect(RowHeaderWidth + 1, Value + 1, Width,
Height);
end;
end;
procedure THeaderGrid.SetColWidth(Value: Integer);
begin
if FColWidth <> Value then
begin
FColWidth := Value;
FCellScroller.HorzScrollBar.Increment := Value;
UpdateSize;
end;
end;
procedure THeaderGrid.SetRowCount(Value: Integer);
begin
if FRowCount <> Value then
begin
FRowCount := Value;
UpdateSize;
end;
end;
procedure THeaderGrid.SetRowHeaderWidth(Value: Integer);
begin
if Value >= 0 then
begin
FRowHeader.Width := Value;
FColHeader.BoundsRect := Rect(Value + 1, 0, Width, ColHeaderHeight);
FCellScroller.BoundsRect := Rect(Value + 1, ColHeaderHeight + 1, Width,
Height);
end;
end;
procedure THeaderGrid.SetRowHeight(Value: Integer);
begin
if FRowHeight <> Value then
begin
FRowHeight := Value;
FCellScroller.VertScrollBar.Increment := Value;
UpdateSize;
end;
end;
procedure THeaderGrid.UpdateSize;
begin
FColHeader.PaintWidth := FColCount * FColWidth;
FRowHeader.PaintHeight := FRowCount * FRowHeight;
FCellScroller.PaintWidth := FColCount * FColWidth;
FCellScroller.PaintHeight := FRowCount * FRowHeight;
end;
procedure THeaderGrid.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
Message.Result := 1;
end;
end.