procedure LeftString: draw left-justified string procedure CenterString: draw centered string procedure RightString: draw right-justified string procedure ClearOutline: draw and clear rectangle procedure Translate: add translation procedure Sweep: sweep area with mouse procedure Zoom: zoom image procedure Capture: capture image as string
link gpxop
May 26, 1999; Gregg M. Townsend
Requires: Version 9 graphics
This file is in the public domain.
This file contains some graphics procedures.
LeftString(x, y, s) draws a string left-aligned at (x, y).
CenterString(x, y, s) draws a string centered at (x, y).
RightString(x, y, s) draws a string right-aligned at (x, y).
ClearOutline(x, y, w, h) draws a rectangle, erasing its interior.
Translate(dx, dy, w, h) moves the window origin and optionally
sets the clipping region.
Zoom(x1, y1, w1, h1, x2, y2, w2, h2)
copies and distorts a rectangle.
Capture(p, x, y, w, h) converts a window area to an image string.
Sweep() lets the user select a rectangular area.
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LeftString(x, y, s), CenterString(x, y, s), and RightString(x, y, s)
draw a string centered vertically about y and left-justified,
centered, or right-justified about x.
ClearOutline(x, y, w, h) draws a rectangle in the foreground color
and fills it with the background color.
Translate(dx, dy, w, h) adjusts a window's dx and dy attributes by
the values given. Note that the resulting attribute values are the
sums of the existing values with the parameters, so that successive
translations accumulate. If w and h are supplied, the clipping
region is set to a rectangle of size (w, h) at the new origin.
Zoom(x1, y1, w1, h1, x2, y2, w2, h2) is a distorting variation of
CopyArea that can be used to shrink or enlarge a rectangular area.
Zero, one, or two window arguments can be supplied. Rectangle 1 is
copied to fill rectangle 2 using simple pixel sampling and replication.
The rectangles can overlap. The usual defaults apply for both rectangles.
Sweep() lets the user select a rectangular area using the mouse.
Called when a mouse button is pressed, Sweep handles all subsequent
events until a mouse button is released. As the mouse moves, a
reverse-mode outline rectangle indicates the selected area. The
pixels underneath the rectangle outline are considered part of this
rectangle, implying a minimum width/height of 1, and the rectangle
is clipped to the window boundary. Sweep returns a list of four
integers [x,y,w,h] giving the rectangle bounds in canonical form
(w and h always positive). Note that w and h give the width as
measured in FillRectangle terms (number of pixels included) rather
than DrawRectangle terms (coordinate difference).
Capture(palette, x, y, w, h) converts a window region into an
image string using the specified palette, and returns the string.
These procedures all accept an optional initial window argument.