Функция построения графика Оформил: DeeCo Автор: http://www.swissdelphicenter.ch private FPoints: array [0..144] of TPoint; {...} procedure TForm1.CalculateGraph; var xRangePixels, yRangePixels: Integer; origin: TPoint; radian, interval: Double; i: Integer; begin { We calculate the sinus curve in the interval -2Pi..+2Pi, with a resolution of 4Pi/144, as a series of points that will be connected by a polyline. The graph is scaled to fit into the paintbox. The origin of the coordinate system is the center of the paintbox. The default windows coordinate system is inverted, the Y axis points downward! } xRangePixels := (paintbox1.Width - 2) div 4; { pixels in Pi } yRangePixels := (paintbox1.Height - 2) div 2; { pixels in 1 } origin := Point(paintbox1.Width div 2, paintbox1.Height div 2); radian := -2.0 * Pi; interval := 4.0 * Pi / 144.0; for i := 0 to High(FPoints) do begin FPoints[i].X := origin.x + Round(radian * xRangePixels / Pi); FPoints[i].Y := origin.y - Round(sin(radian) * yRangePixels); radian := radian + interval; end; end; procedure TForm1.PaintBox1Paint(Sender: TObject); var origin: TPoint; xRangePixels, yRangePixels: Integer; begin with PaintBox1.Canvas do begin { Fill background in white } Brush.Color := clBtnFace; Brush.Style := bsSolid; Fillrect(paintbox1.BoundsRect); { Paint a coordinate cross } origin := Point(paintbox1.Width div 2, paintbox1.Height div 2); Pen.Color := clBlack; Pen.Style := psSolid; Pen.Width := 1; MoveTo(1, origin.Y); LineTo(paintbox1.Width - 1, origin.y); MoveTo(origin.x, 1); LineTo(origin.x, paintbox1.Height - 1); { Paint some tickmarks and label the axis } Font.Name := 'Symbol'; Font.Size := 8; Font.Color := clBlack; xRangePixels := (paintbox1.Width - 2) div 4; { pixels in Pi } yRangePixels := (paintbox1.Height - 2) div 2; { pixels in 1 } { X axis } MoveTo(origin.x - 2 * xRangePixels, origin.y - 4); LineTo(origin.x - 2 * xRangePixels, origin.y + 4); TextOut(origin.x - 2 * xRangePixels + 2, origin.y + 2, '-2p'); MoveTo(origin.x - xRangePixels, origin.y - 4); LineTo(origin.x - xRangePixels, origin.y + 4); TextOut(origin.x - xRangePixels + 2, origin.y + 2, '-p'); MoveTo(origin.x + xRangePixels, origin.y - 4); LineTo(origin.x + xRangePixels, origin.y + 4); TextOut(origin.x + xRangePixels - 2 - TextWidth('p'), origin.y + 2, 'p'); MoveTo(origin.x + 2 * xRangePixels, origin.y - 4); LineTo(origin.x + 2 * xRangePixels, origin.y + 4); TextOut(origin.x + 2 * xRangePixels - 2 - TextWidth('2p'), origin.y + 2, '2p'); { Y axis } MoveTo(origin.x - 4, origin.y - yRangePixels); LineTo(origin.x + 4, origin.y - yRangePixels); TextOut(origin.x + 4, origin.y - yRangePixels, '1.0'); MoveTo(origin.x - 4, origin.y - yRangePixels div 2); LineTo(origin.x + 4, origin.y - yRangePixels div 2); TextOut(origin.x + 4, origin.y - (yRangePixels + TextHeight('1')) div 2, '0.5'); MoveTo(origin.x - 2, origin.y + yRangePixels div 2); LineTo(origin.x + 2, origin.y + yRangePixels div 2); TextOut(origin.x + 3, origin.y + (yRangePixels - TextHeight('1')) div 2, '-0.5'); MoveTo(origin.x - 2, origin.y + yRangePixels); LineTo(origin.x + 2, origin.y + yRangePixels); TextOut(origin.x + 3, origin.y + yRangePixels - TextHeight('1'), '-1.0'); {Paint the graph } Pen.Color := clBlue; Polyline(FPoints); end; end; procedure TForm1.FormResize(Sender: TObject); begin CalculateGraph; end; procedure TForm1.FormCreate(Sender: TObject); begin CalculateGraph; end;
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