PDF_curveto()

(PHP 4, PECL pdflib >= 1.0.0)

Draw Bezier curve

说明

PDF_curveto(resource $p,float $x1,float $y1,float $x2,float $y2,float $x3,float $y3): bool

Draws a Bezier curve from the current point, using 3 more control points.成功时返回TRUE，或者在失败时返回FALSE。

function pdf_ellipse_inscribed ($pdfobj,$x,$y,$width,$height) {
// Function to draw an ellipse inscribed in a rectangle 
// described by lower left (x,y) with width and height.
  pdf_moveto($pdfobj, $x,$y+$height/2);
  pdf_curveto($pdfobj, $x,$y+$height/2,$x,$y+$height,$x+$width/2,$y+$height);
  pdf_curveto($pdfobj, $x+$width/2,$y+$height,$x+$width,$y+$height,$x+$width,$y+$height/2);
  pdf_curveto($pdfobj, $x+$width,$y+$height/2,$x+$width,$y,$x+$width/2,$y);
  pdf_curveto($pdfobj, $x+$width/2,$y,$x,$y,$x,$y+$height/2);
}

Rod's function does not work (the thing produced is not even symmetrical).
Here is one that produces a correct approximation to an ellipse:
function pdf_ellipse ($pdfobj,$x,$y,$width,$height) {
// Function to draw an ellipse inscribed in a rectangle
// described by lower left (x,y) with width and height.
 $fac = (4*sqrt(2)-4)/3;
 $dx = $width*(1-$fac)/2;
 $dy = $height*(1-$fac)/2;
 pdf_moveto($pdfobj, $x,$y+$height/2);
 pdf_curveto($pdfobj, $x,$y+$height-$dy, $x+$dx,$y+$height, $x+$width/2,$y+$height);
 pdf_curveto($pdfobj, $x+$width-$dx,$y+$height, $x+$width,$y+$height-$dy, $x+$width,$y+$height/2);
 pdf_curveto($pdfobj, $x+$width,$y+$dy, $x+$width-$dx,$y, $x+$width/2,$y);
 pdf_curveto($pdfobj, $x+$dx,$y, $x,$y+$dy, $x,$y+$height/2);
}