extending pst-gradient

Fri Apr 10 19:32:31 CEST 1998

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>>>>> "Gerges.Mariano" == MARIANO Georges <mariano at terre.inrets.fr> writes:

    Gerges.Mariano> I need to extend pst-gradient to allow "circle gradient"

  Yesterday evening, I built an user interface to my old PostScript hack to
allow gradients with a circle form. I just finish to clean it up.

  Usage is straightforward. Parameters are GradientCircle, GradientPos and
GradientScale. See the following examples.

  P.S. I also add minor tick marks (normal or logarithmic) to \psaxes. But it
must be validate first.

D.G.

\documentclass{minimal}

\usepackage{pst-grad}

\makeatletter

% D.G. - April 1998

% To define the gradient as linear or as circle
\newif\ifGradientCircle
\def\psset at GradientCircle#1{\@nameuse{GradientCircle#1}}
\psset at GradientCircle{false}

% Position of the center of the gradient
\def\psset at GradientPos#1{\psset@@GradientPos#1}
\def\psset@@GradientPos(#1){\edef\ps at GradientPos{#1}}
\psset at GradientPos{(0,0)}

% Scale factor
\def\psset at GradientScale#1{\edef\ps at GradientScale{#1}}
\psset at GradientScale{1}

\def\psfs at gradient{%
% D.G. modification begin - Apr.  9, 1998
%\addto at pscode{gsave
\pst at getcoor{\ps at GradientPos}{\pst at tempa}
\addto at pscode{gsave
    \ifGradientCircle true \else false \fi
    \ps at GradientScale\space
    \pst at tempa
% D.G. modification end
    gsave \pst at usecolor\psgradbegin currentrgbcolor grestore
    gsave \pst at usecolor\psgradend currentrgbcolor grestore
    \psgradlines
    \psgradmidpoint
    \psk at gradangle
    tx at GradientDict begin GradientFill end grestore}}

\makeatother

\begin{document}

\psset{linestyle=none,fillstyle=gradient,gradmidpoint=0,gradend=white}

\psset{gradbegin=red}
\begin{pspicture}(-2,-2)(2,2)
  \pscircle{2}
\end{pspicture}
\psset{GradientCircle=true}
\begin{pspicture}(-2,-2)(2,2)
  \pscircle{2}
\end{pspicture}
\begin{pspicture}(-2,-2)(2,2)
  \pscircle[GradientPos={(2,1)}]{2}
\end{pspicture}

\psset{gradbegin=green}
\begin{pspicture}(4,3)
  \psframe(4,2)
\end{pspicture}
\begin{pspicture}(4,3)
  \psframe[GradientPos={(2,1)}](4,2)
\end{pspicture}
\begin{pspicture}(4,3)
  \psframe[GradientPos={(3.5,1.5)}](4,2)
\end{pspicture}

\begin{pspicture}(4,3)
  \psframe(4,2)
\end{pspicture}
\begin{pspicture}(4,3)
  \psframe[GradientScale=3](4,2)
\end{pspicture}
\begin{pspicture}(4,3)
  \psframe[GradientScale=6](4,2)
\end{pspicture}

\psset{gradbegin=cyan}
\begin{pspicture}(2,-1)(6,2)
  \psframe(2,-1)(6,1)
\end{pspicture}
\begin{pspicture}(2,-1)(6,2)
  \psframe[gradmidpoint=0.5,GradientPos={(2.5,0.5)}](2,-1)(6,1)
\end{pspicture}
\begin{pspicture}(2,-1)(6,2)
  \psframe[gradmidpoint=1,GradientPos={(4,1)}](2,-1)(6,1)
\end{pspicture}

\begin{pspicture}(-2.5,-1.25)(2.5,1.25)
  \psellipse[gradbegin=blue,GradientScale=2](2.5,1.25)
\end{pspicture}
\begin{pspicture}(3,4)
  \pspolygon[gradbegin=black](0,0)(1,3)(3,2)(1.5,2)(2,0.5)
\end{pspicture}
\begin{pspicture}(3,4)
  \psdiamond[gradbegin=magenta,gradend=yellow](1.5,1)(1.5,1)
\end{pspicture}

\end{document}

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%!
% PostScript prologue for pst-grad.tex.
% Version 97.1, 98/04/09 (adding GradientCircle style - D.G.)
% For copying restrictions, see pstricks.tex.
%
% For the PSTricks gradient fillstyle.
%
% Based on some EPS files by leeweyr!bill at nuchat.sccsi.com (W. R. Lee).
%
% Syntax:
% D.G. modification begin - Apr.  9, 1998
%%%%%% R0 G0 B0 R1 G1 B1 NumLines MidPoint Angle GradientFill
%   ifGradientCircle GradientScale GradientPosX GradientPosY
%     R0 G0 B0 R1 G1 B1 NumLines MidPoint Angle GradientFill
% D.G. modification end

/tx at GradientDict 40 dict def
tx at GradientDict begin
/GradientFill {
  rotate
  /MidPoint ED
  /NumLines ED
  /LastBlue ED
  /LastGreen ED
  /LastRed ED
  /FirstBlue ED
  /FirstGreen ED
  /FirstRed ED
% D.G. modification begin - Apr.  9, 1998
  /GradientPosY ED
  /GradientPosX ED
  /GradientScale ED
  /ifGradientCircle ED
% D.G. modification end
  % This avoids gaps due to rounding errors:
  clip
  pathbbox           %leave llx,lly,urx,ury on stack
% D.G. modification begin - Apr. 10, 1998
  4 copy /ury ED /urx ED /lly ED /llx ED
% D.G. modification end
  /y ED /x ED
% D.G. modification begin - Apr. 10, 1998
  ifGradientCircle
   {0 GradientPosX eq {0 GradientPosX eq {2 copy translate} if} if}
   {2 copy translate} ifelse
% D.G. modification end
  y sub neg /y ED
  x sub neg /x ED
  % This avoids gaps due to rounding errors:
  LastRed FirstRed add 2 div
  LastGreen FirstGreen add 2 div
  LastBlue FirstBlue add 2 div
  setrgbcolor
% D.G. modification begin - Jul. 23, 1997 / Apr.  9, 1998
  ifGradientCircle
   {/YSizePerLine y NumLines div def
    /CurrentY y 2 div def
    /MidLine NumLines 2 div 1 MidPoint sub mul abs cvi def}
   {fill
    /YSizePerLine y NumLines div def
    /CurrentY 0 def
    /MidLine NumLines 1 MidPoint sub mul abs cvi def} ifelse
% DG modification end
  MidLine NumLines 2 sub gt
  { /MidLine NumLines def }
  { MidLine 2 lt { /MidLine 0 def } if }
  ifelse
  MidLine 0 gt
  {
    /Red FirstRed def
    /Green FirstGreen def
    /Blue FirstBlue def
    /RedIncrement LastRed FirstRed sub MidLine 1 sub div def
    /GreenIncrement LastGreen FirstGreen sub MidLine 1 sub div def
    /BlueIncrement LastBlue FirstBlue sub MidLine 1 sub div def
    MidLine { GradientLoop } repeat
  } if
  MidLine NumLines lt
  {
    /Red LastRed def
    /Green LastGreen def
    /Blue LastBlue def
    /RedIncrement FirstRed LastRed sub NumLines MidLine sub 1 sub div def
    /GreenIncrement FirstGreen LastGreen sub NumLines MidLine sub 1 sub div def
    /BlueIncrement FirstBlue LastBlue sub NumLines MidLine sub 1 sub div def
    NumLines MidLine sub { GradientLoop } repeat
  } if
} def
/GradientLoop {
% D.G. modification begin - Jul. 23, 1997 / Apr.  9, 1998
  ifGradientCircle
   {CurrentY 0 gt {
% The default center used is the center of the bounding box of the object
      0 GradientPosX eq
        {0 GradientPosX eq
           {/GradientPosX urx llx sub 2 div def
            /GradientPosY ury lly sub 2 div def} if} if
      GradientPosX GradientPosY CurrentY GradientScale mul 0 360 arc
      Red Green Blue setrgbcolor fill
      /CurrentY CurrentY YSizePerLine sub def
      /Blue Blue BlueIncrement add def
      /Green Green GreenIncrement add def
      /Red Red RedIncrement add def} if}
   {0 CurrentY moveto
    x 0 rlineto
    0 YSizePerLine rlineto
    x neg 0 rlineto
    closepath
    Red Green Blue setrgbcolor fill
    /CurrentY CurrentY YSizePerLine add def
    /Blue Blue BlueIncrement add def
    /Green Green GreenIncrement add def
    /Red Red RedIncrement add def} ifelse
% D.G. modification end
} def

end
% END pst-grad.pro

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