monochrome and pstricks

Question

I am creating a file type images for presentation / written, I have been interested in the monochrome package xcolor, but by using it I have not obtained the expected results, check the documentation for pstricks but , this is very old and refers to an obsolete package (pstcol), an image to illustrate what I need:

and the MWE:

\documentclass[10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[monochrome]{xcolor}
\usepackage{pstricks-add}
\pagestyle{empty}
\begin{document}
\begin{pspicture*}(-0.5,-0.5)(5,3.5)
\psset{unit=1.0cm,algebraic=true,dimen=middle,linewidth=0.8pt}
\pscustom[linewidth=0.7pt,linecolor=red,fillcolor=red,fillstyle=solid,opacity=0.25]{
\parametricplot{-2.39}{-1.14}{0.52*cos(t)+3.25|0.52*sin(t)+3}
\lineto(3.25,3)\closepath}
\pspolygon[linewidth=0.7pt,linecolor=cyan,fillcolor=green,fillstyle=solid,opacity=0.25](0.25,0.25)(3.25,3)(4.5,0.25)
\begin{scriptsize}
\uput[d](0.25,0.25){\red{$A$}}
\uput[u](3.25,3){\red{$B$}}
\uput[d](4.5,0.25){\red{$C$}}
\uput{7pt}[-100](3.25,3){\red{$\alpha$}}
\end{scriptsize}
\end{pspicture*}
\end{document}

Clarification: Not grayscale, an image in "black and white", modify a single image is no problem, what I want is to turn the colors in a "global" for a document (50 images). In the "Frequently Asked Questions" from the documentation of "pstricks" (pag 304) describes the process with a code like the following:

\usepackage[monochrome]{pstcol}
% ...
\makeatletter
\def\PSTricksMonochrome{%
\def\psset@bordercolor##1{\pst@getcolor{white}{\psbordercolor}}%
\def\psset@doublecolor##1{\pst@getcolor{white}{\psdoublecolor}}%
\def\psset@shadowcolor##1{\pst@getcolor{darkgray}{\psshadowcolor}}%
\def\psset@linecolor##1{\pst@getcolor{black}{\pslinecolor}}%
\def\psset@fillcolor##1{\pst@getcolor{white}{\psfillcolor}}%
\def\psset@gridcolor##1{\pst@getcolor{black}{\psgridcolor}}%
\def\psset@gridlabelcolor##1{\pst@getcolor{black}{\psgridlabelcolor}}%
\def\psset@hatchcolor##1{\pst@getcolor{black}{\pshatchcolor}}%
\def\psset@subgridcolor##1{\pst@getcolor{gray}{\pssubgridcolor}}}
\makeatother

It does not work an today.

Answer 1

your code looks like an complicated export from a graphical program and as Karl already pointed out it is not clear what exactly do you want: the image in grayscale or an automatic conversion from color to monochrome? However, here is a correct code for a black and white output:

\documentclass[10pt]{article}
\usepackage{pstricks}\SpecialCoor
\pagestyle{empty}
\begin{document}
\begin{pspicture}(-0.5,-0.5)(5,3.5)
\psarc(3.25,3){0.5}{(-3,-2.75)}{(1.25,-2.75)}
\pspolygon(0.25,0.25)(3.25,3)(4.5,0.25)
\scriptsize
\uput[d](0.25,0.25){$A$}
\uput[u](3.25,3){$B$}
\uput[d](4.5,0.25){$C$}
\uput{7pt}[-100](3.25,3){$\alpha$}
\end{pspicture}
\end{document}

an automatic conversion into grayscale is possible with the following statement in your preamble:

\AtBeginDocument{\special{ps:
/setrgbcolor { 0.07 mul exch 0.71 mul add exch 0.21 mul add setgray } def 
}}

with the pstricks.sty from http://texnik.dante.de/tex/latex/pstricks/ you can use

\usepackage[monochrome]{pstricks}

then it is done by the package.

You can also overwrite the definition for the keys in your documents preamble, eg for hatchcolor

\makeatletter
\define@key[psset]{pstricks}{hatchcolor}[black]{\pst@getcolor{black}\pshatchcolor}
\makeatother

Answer 2

I'm not sure to correctly understand, but I think you want a non-filled image.

So, try to substitute your corresponding lines with:

\pscustom[linewidth=0.7pt,opacity=0.25]{
\parametricplot{-2.39}{-1.14}{0.52*cos(t)+3.25|0.52*sin(t)+3}
\lineto(3.25,3)\closepath}
\pspolygon[linewidth=0.7pt,opacity=0.25](0.25,0.25)(3.25,3)(4.5,0.25)