YOUSEFUL / DELPHI / COMPONENTS

`TAtlasCanvasSurface`

Drawing surface over any VCL TCanvas: screen, bitmap, metafile or printer.

Class Unit Atlas.PlotSurface · Inherits TAtlasPlotSurface · Product Atlas Plot

Description

Implements every TAtlasPlotSurface method with GDI calls on the canvas it was given. The chart uses it for painting, RenderTo, CreateBitmap and bitmap and metafile exports. Create one yourself to draw several charts onto one canvas with TAtlasPlot.Render. The surface does not own the canvas.

Members

Member	Kind	What it does
`Create`	constructor	Wraps `Canvas`, which must outlive the surface.
`Destroy`	destructor	Ends an open clip, restoring the canvas's previous clip region.
`UsePen`	method	GDI draws dashes only at width 1, so a dashed pen is always one pixel wide and dotted.
`BeginClip`	method	Intersects the canvas clip with `Bounds`, keeping any clip the caller had (printing, `PaintTo`) and restoring it in `EndClip`.
`EndClip`	method	Restores the clip region saved by `BeginClip`.

Constructors

`Create` constructor

constructor Create(Canvas: TCanvas);

Wraps Canvas, which must outlive the surface.

Destructors

`Destroy` destructor

destructor Destroy; override;

Ends an open clip, restoring the canvas's previous clip region.

Methods

`UsePen` method

procedure UsePen(Color: TColor; Width: Integer = 1; Dashed: Boolean = False); override;

GDI draws dashes only at width 1, so a dashed pen is always one pixel wide and dotted. Dashed strokes are drawn with a clear brush so the gaps stay transparent.

`BeginClip` method

procedure BeginClip(const Bounds: TRect); override;

Intersects the canvas clip with Bounds, keeping any clip the caller had (printing, PaintTo) and restoring it in EndClip.

`EndClip` method

procedure EndClip; override;

Restores the clip region saved by BeginClip.

Examples

Two charts on one bitmap

Renders two charts side by side into a single image.

uses
  System.Types, Vcl.Graphics, Atlas.Plot, Atlas.PlotSurface;

function SideBySide(Left, Right: TAtlasPlot): Vcl.Graphics.TBitmap;
var
  Surface: TAtlasCanvasSurface;
begin
  Result := Vcl.Graphics.TBitmap.Create;
  try
    Result.SetSize(1200, 400);
    Surface := TAtlasCanvasSurface.Create(Result.Canvas);
    try
      Left.Render(Surface, Rect(0, 0, 600, 400));
      Right.Render(Surface, Rect(600, 0, 1200, 400));
    finally
      Surface.Free;
    end;
  except
    Result.Free;
    raise;
  end;
  // Render leaves the hit regions of the last render; repaint charts that are on screen.
  if Left.Showing then Left.Repaint;
  if Right.Showing then Right.Repaint;
end;

TAtlasPlotSurface · TAtlasSvgSurface · TAtlasPlot

Also in Atlas Plot

TAtlasPlot

TAtlasCanvasSurface