Documentation Index
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Overview
TRender is the base class for all custom rendering shapes in TeeGrid. It provides the foundation for painting cells, headers, and other grid elements with custom visual representations.
The rendering system in TeeGrid includes specialized renderers like TFormatRender, TTextRender, TBooleanRender, TExpanderRender, and TProgressRender.
Unit: Tee.Renders.pas
Class Hierarchy
TPersistentChange
└── TRender
└── TFormatRender
├── TTextRender
│ ├── TVisibleTextRender
│ │ ├── TCellRender
│ │ └── THover
│ ├── TBoxRender
│ │ ├── TBooleanRender
│ │ └── TExpanderRender
│ └── TPasswordRender
└── TProgressRender
TRender Base Class
Methods
Paint
procedure Paint(var AData: TRenderData); virtual;
AData: Rendering data containing bounds, painter, data value, and row index
Example:
var
Render: TRender;
Data: TRenderData;
begin
Render := TTextRender.Create(nil);
try
Data.Bounds := RectF(0, 0, 100, 25);
Data.Data := 'Hello World';
Data.Painter := MyPainter;
Data.Row := 0;
Render.Paint(Data);
finally
Render.Free;
end;
end;
Hit
function Hit(const R: TRectF; const X, Y: Single): Boolean; virtual;
R: Rectangle boundsX, Y: Point coordinates
Returns: True if the point hits the render area
TRenderData Record
The TRenderData record contains all information needed for rendering:
type
TRenderData = record
Bounds: TRectF; // Rectangle to paint within
Data: String; // Cell data (as string)
Painter: TPainter; // Painter instance for drawing
Row: Integer; // Row index
function AsBoolean: Boolean;
procedure ClearData;
function IsEmpty: Boolean;
end;
Methods
AsBoolean: Converts data to boolean valueClearData: Clears the data stringIsEmpty: Checks if data is empty
Rectangle shape renderer with borders and format support.
Properties
Borders
property Borders: TBorders read GetBorders write SetBorders;
Render.Borders.Left.Visible := True;
Render.Borders.Left.Color := clBlue;
Render.Borders.Left.Size := 2;
property Format: TTextFormat read GetFormat write SetFormat;
Methods
function HasFormat: Boolean;
True if format properties are assigned.
StrokeHeight
function StrokeHeight: Single;
TTextRender
Rectangle renderer with text, margins, and alignment support.
Properties
Margins
property Margins: TMargins read GetMargins write SetMargins;
Render.Margins.Left.Value := 4;
Render.Margins.Top.Value := 2;
Render.Margins.Right.Value := 4;
Render.Margins.Bottom.Value := 2;
TextAlign
property TextAlign: TTextAlign read FAlign write SetAlign;
Render.TextAlign.Horizontal := THorizontalAlign.Center;
Render.TextAlign.Vertical := TVerticalAlign.Center;
Trimming
property Trimming: TTextTrimming read GetTrimming write SetTrimming;
Render.Trimming.Mode := TTrimmingMode.Character;
Render.Trimming.Ellipsi := True;
Methods
CalcHeight
function CalcHeight(const APainter: TPainter): Single; overload;
function CalcHeight(const APainter: TPainter; const AText: String): Single; overload;
APainter: Painter instance for text measurementAText: Text to measure (optional)
Returns: Required height in pixels
TBooleanRender
Checkbox-style renderer for boolean values.
Properties
Style
property Style: TBooleanRenderStyle read FStyle write SetStyle;
TBooleanRenderStyle.Check: Checkbox with checkmarkTBooleanRenderStyle.Text: Text representation (“True”/“False”)
property CheckFormat: TFormat read FCheckFormat write SetCheckFormat;
var
BoolRender: TBooleanRender;
begin
BoolRender := TBooleanRender.Create(nil);
BoolRender.Style := TBooleanRenderStyle.Check;
BoolRender.CheckFormat.Stroke.Color := clGreen;
BoolRender.CheckFormat.Stroke.Size := 2;
end;
TExpanderRender
Expander renderer with plus/minus, triangle, or arrow styles.
Properties
Style
property Style: TExpanderStyle read FStyle write SetStyle;
TExpanderStyle.PlusMinus: Plus/minus symbolsTExpanderStyle.Triangle: Triangle shapesTExpanderStyle.Arrow: Arrow symbols
AlwaysExpand
property AlwaysExpand: Boolean read FAlwaysExpand write FAlwaysExpand;
property ExpandFormat: TFormat read FExpandFormat write SetExpandFormat;
ExpandLine
property ExpandLine: TStroke read FExpandLine write SetExpandLine;
Events
OnCanExpand
property OnCanExpand: TExpanderEvent read FOnCanExpand write FOnCanExpand;
type
TExpanderEvent = function(const Sender: TRender; const ARow: Integer): Boolean of object;
OnExpand
property OnExpand: TExpanderEvent read FOnExpand write FOnExpand;
OnGetExpanded
property OnGetExpanded: TExpanderEvent read FOnGetExpanded write FOnGetExpanded;
function TForm1.ExpanderCanExpand(const Sender: TRender; const ARow: Integer): Boolean;
begin
Result := HasChildren(ARow);
end;
function TForm1.ExpanderGetExpanded(const Sender: TRender; const ARow: Integer): Boolean;
begin
Result := FExpandedRows.Contains(ARow);
end;
procedure TForm1.SetupExpander;
begin
Expander.Style := TExpanderStyle.Triangle;
Expander.OnCanExpand := ExpanderCanExpand;
Expander.OnGetExpanded := ExpanderGetExpanded;
end;
Methods
Expand
procedure Expand(const ARow: Integer);
PaintLines
procedure PaintLines(var AData: TRenderData);
TProgressRender
Progress bar renderer showing percentage completion.
Properties
Minimum
property Minimum: Single read FMin write SetMin;
Maximum
property Maximum: Single read FMax write SetMax;
Orientation
property Orientation: TOrientation read FOrientation write SetOrientation;
TOrientation.Horizontal: Left to right fillTOrientation.Vertical: Bottom to top fill
Example:
var
ProgressRender: TProgressRender;
begin
ProgressRender := TProgressRender.Create(nil);
ProgressRender.Minimum := 0;
ProgressRender.Maximum := 100;
ProgressRender.Orientation := TOrientation.Horizontal;
ProgressRender.Format.Brush.Color := clGreen;
end;
TPasswordRender
Text renderer that masks password characters.
Example:
var
PassRender: TPasswordRender;
begin
PassRender := TPasswordRender.Create(nil);
// Automatically masks text as '***'
end;
TShapePainter Helper
Utility class for painting common shapes.
Methods
Check
class procedure Check(const APainter: TPainter; const ARect: TRectF); static;
PlusMinus
class procedure PlusMinus(const APainter: TPainter; const ARect: TRectF; const IsExpanded: Boolean); static;
Arrow.Down / Arrow.Right
class procedure TArrow.Down(const APainter: TPainter; const ARect: TRectF); static;
class procedure TArrow.Right(const APainter: TPainter; const ARect: TRectF); static;
Triangle.LeftRight / Triangle.TopBottom
class procedure TTriangle.LeftRight(const APainter: TPainter; const ARect: TRectF); static;
class procedure TTriangle.TopBottom(const APainter: TPainter; const ARect: TRectF); static;
Creating Custom Renderers
To create a custom renderer, inherit from TRender or one of its descendants:
type
TMyCustomRender = class(TTextRender)
public
procedure Paint(var AData: TRenderData); override;
end;
procedure TMyCustomRender.Paint(var AData: TRenderData);
begin
// Custom painting logic
inherited; // Call base class if needed
// Additional custom drawing
AData.Painter.SetBrush(Format.Brush);
AData.Painter.FillEllipse(AData.Bounds);
end;
See Also
