1Tk_CanvasPs(3)               Tk Library Procedures              Tk_CanvasPs(3)
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NAME

8       Tk_CanvasPsY,   Tk_CanvasPsBitmap,  Tk_CanvasPsColor,  Tk_CanvasPsFont,
9       Tk_CanvasPsPath, Tk_CanvasPsStipple - utility procedures for generating
10       Postscript for canvases
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SYNOPSIS

13       #include <tk.h>
14
15       double
16       Tk_CanvasPsY(canvas, canvasY)
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18       int
19       Tk_CanvasPsBitmap(interp, canvas, bitmap, x, y, width, height)
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21       int
22       Tk_CanvasPsColor(interp, canvas, colorPtr)
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24       int
25       Tk_CanvasPsFont(interp, canvas, tkFont)
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27       Tk_CanvasPsPath(interp, canvas, coordPtr, numPoints)
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29       int
30       Tk_CanvasPsStipple(interp, canvas, bitmap)
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ARGUMENTS

33       Tk_Canvas      canvas      (in)      A  token  that identifies a canvas
34                                            widget  for  which  Postscript  is
35                                            being generated.
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37       double         canvasY     (in)      Y-coordinate  in  the space of the
38                                            canvas.
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40       Tcl_Interp     *interp     (in/out)  A Tcl interpreter;  Postscript  is
41                                            appended  to  its  result,  or the
42                                            result may  be  replaced  with  an
43                                            error message.
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45       Pixmap         bitmap      (in)      Bitmap to use for generating Post‐
46                                            script.
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48       int            x           (in)      X-coordinate within bitmap of left
49                                            edge of region to output.
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51       int            y           (in)      Y-coordinate  within bitmap of top
52                                            edge of region to output.
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54       int            width       (in)      Width of region of bitmap to  out‐
55                                            put, in pixels.
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57       int            height      (in)      Height of region of bitmap to out‐
58                                            put, in pixels.
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60       XColor         *colorPtr   (in)      Information about color  value  to
61                                            set in Postscript.
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63       Tk_Font        tkFont      (in)      Font for which Postscript is to be
64                                            generated.
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66       double         *coordPtr   (in)      Pointer to an array of coordinates
67                                            for  one  or more points specified
68                                            in canvas coordinates.  The  order
69                                            of  values  in coordPtr is x1, y1,
70                                            x2, y2, x3, y3, and so on.
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72       int            numPoints   (in)      Number of points at coordPtr.
73_________________________________________________________________
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75

DESCRIPTION

77       These procedures are called by canvas type managers to carry out common
78       functions  related  to  generating  Postscript.  Most of the procedures
79       take a canvas argument, which refers to a canvas widget for which Post‐
80       script is being generated.
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82       Tk_CanvasPsY  takes as argument a y-coordinate in the space of a canvas
83       and returns the value that should be used for that point in  the  Post‐
84       script  currently  being  generated  for canvas.  Y coordinates require
85       transformation because Postscript uses an origin at the lower-left cor‐
86       ner  whereas X uses an origin at the upper-left corner.  Canvas x coor‐
87       dinates can be used directly in Postscript without transformation.
88
89       Tk_CanvasPsBitmap generates Postscript to describe a region of  a  bit‐
90       map.  The Postscript is generated in proper image data format for Post‐
91       script, i.e., as data between angle brackets, one bit per  pixel.   The
92       Postscript  is appended to interp->result and TCL_OK is returned unless
93       an error occurs, in which case TCL_ERROR is returned and interp->result
94       is overwritten with an error message.
95
96       Tk_CanvasPsColor  generates Postscript to set the current color to cor‐
97       respond to its colorPtr argument, taking into  account  any  color  map
98       specified  in  the  postscript  command.   It appends the Postscript to
99       interp->result and returns TCL_OK unless an error occurs, in which case
100       TCL_ERROR  is  returned and interp->result is overwritten with an error
101       message.
102
103       Tk_CanvasPsFont generates Postscript that  sets  the  current  font  to
104       match  tkFont  as  closely  as  possible.   Tk_CanvasPsFont  takes into
105       account any font map specified in the postscript command, and  it  does
106       the best it can at mapping X fonts to Postscript fonts.  It appends the
107       Postscript to interp->result and returns TCL_OK unless an error occurs,
108       in  which  case TCL_ERROR is returned and interp->result is overwritten
109       with an error message.
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111       Tk_CanvasPsPath generates Postscript to set the current path to the set
112       of  points  given  by coordPtr and numPoints.  It appends the resulting
113       Postscript to interp->result.
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115       Tk_CanvasPsStipple generates Postscript that will fill the current path
116       in  stippled  fashion.   It  uses bitmap as the stipple pattern and the
117       current Postscript color;  ones in the stipple bitmap are drawn in  the
118       current  color,  and  zeroes  are  not drawn at all.  The Postscript is
119       appended to interp->result and TCL_OK  is  returned,  unless  an  error
120       occurs, in which case TCL_ERROR is returned and interp->result is over‐
121       written with an error message.
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KEYWORDS

125       bitmap, canvas, color, font, path, Postscript, stipple
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129Tk                                    4.0                       Tk_CanvasPs(3)
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