Standard Library
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Package graph-plotmisc (in graph.i) - miscellaneous plotting-related functions
Index of documented functions or symbols:
DOCUMENT bytscl(z)
or bytscl(z, top=max_byte, cmin=lower_cutoff, cmax=upper_cutoff)
returns a char array of the same shape as Z, with values linearly
scaled to the range 0 to one less than the current palette size.
If MAX_BYTE is specified, the scaled values will run from 0 to
MAX_BYTE instead.
If LOWER_CUTOFF and/or UPPER_CUTOFF are specified, Z values outside
this range are mapped to the cutoff value; otherwise the linear
scaling maps the extreme values of Z to 0 and MAX_BYTE.
SEE ALSO: plf, pli, histeq_scale
DOCUMENT nc= contour(yc,xc, level, z, y,x)
or nc= contour(yc,xc, level, z, y,x,ireg)
returns the points on the contour curve that would have been
plotted by plc. Z, Y, X, and IREG are as for plc, and the
triangle= and region= keywords are accepted and have the same
meaning as for plc. Unlike plc, the triangle array is an output
as well as an input to contour; if supplied it may be modified
to reflect any triangulations which were performed by contour.
LEVEL is a scalar z value to return the points at that contour
level. All such points lie on edges of the mesh. If a contour
curve closes, the final point is the same as the initial point
(i.e.- that point is included twice in the returned list).
LEVEL is a pair of z values [z0,z1] to return the points of
a set of polygons which outline the regions between the two
contour levels. These will include points on the mesh boundary
which lie between the levels, in addition to the edge points
for both levels. The polygons are closed, simply connected,
and will not contain more than about 4000 points (larger polygons
are split into pieces with a few points repeated where the pieces
join).
YC and XC are the output points on the curve(s), or nil if there
are no points. On input, they must be simple variable references,
not expressions. The return value NC is a list of the lengths of
the polygons/polylines returned in (XC,YC), or nil if there are
none. numberof(XC)==numberof(YC)==sum(NC). For the level pair
case, YC, XC, and NC are ready to be used as inputs to plfp.
KEYWORDS: triangle, region
DOCUMENT histeq_scale(z, top=top_value, cmin=cmin, cmax=cmax) returns a byte-scaled version of the array Z having the property that each byte occurs with equal frequency (Z is histogram equalized). The result bytes range from 0 to TOP_VALUE, which defaults to one less than the size of the current palette (or 255 if no pli, plf, or palette command has yet been issued). If non-nil CMIN and/or CMAX is supplied, values of Z beyond these cutoffs are not included in the frequency counts.
DOCUMENT mesh_loc(y0, x0)
or mesh_loc(y0, x0, y, x)
or mesh_loc(y0, x0, y, x, ireg)
returns the zone index (=i+imax*(j-1)) of the zone of the mesh
(X,Y) (with optional region number array IREG) containing the
point (X0,Y0). If (X0,Y0) lies outside the mesh, returns 0.
Thus, eg- ireg(mesh_loc(x0, y0, y, x, ireg)) is the region number of
the region containing (x0,y0). If no mesh specified, uses default.
X0 and Y0 may be arrays as long as they are conformable.
For mesh_loc wrappers to duplicate the functionality of the
digitize and interp functions in 2D, see the library file digit2.i.
After #include "digit2.i", type: help,digit2
DOCUMENT result= mouse(system, style, prompt)
displays a PROMPT, then waits for a mouse button to be pressed,
then released. Returns array of eleven doubles:
result= [x_pressed, y_pressed, x_released, y_released,
xndc_pressed, yndc_pressed, xndc_released, yndc_released,
system, button, modifiers]
If SYSTEM>=0, the first four coordinate values will be relative to
that coordinate system.
For SYSTEM<0, the first four coordinate values will be relative to
the coordinate system under the mouse when the button was pressed.
The second four coordinates are always normalized device coordinates,
which start at (0,0) in the lower left corner of the 8.5x11 sheet of
paper the picture will be printed on, with 0.0013 NDC unit being
1/72.27 inch (1.0 point). Look in the style sheet for the location
of the viewport in NDC coordinates (see the style keyword).
If STYLE is 0, there will be no visual cues that the mouse
command has been called; this is intended for a simple click.
If STYLE is 1, a rubber band box will be drawn; if STYLE is 2,
a rubber band line will be drawn. These disappear when the
button is released.
Clicking a second button before releasing the first cancels the
mouse function, which will then return nil.
Ordinary text input also cancels the mouse function, which again
returns nil.
The left button reverses forground for background (by XOR) in
order to draw the rubber band (if any). The middle and right
buttons use other masks, in case the rubber band is not visible
with the left button.
long(result(9)) is the coordinate system in which the first four
coordinates are to be interpreted.
long(result(10)) is the button which was pressed, 1 for left, 2
for middle, and 3 for right (4 and 5 are also possible).
long(result(11)) is a mask representing the modifier keys which
were pressed during the operation: 1 for shift, 2 for shift lock,
4 for control, 8 for mod1 (alt or meta), 16 for mod2, 32 for mod3,
64 for mod4, and 128 for mod5.
Holding the shift key and pressing the left mouse button is
equivalent to pressing the middle mouse button. Similarly,
pressing meta-left is equivalent to the right button. This
permits access to the middle and right button functions on
machines (e.g.- most laptops) with two button or one button
mice. The long(result(10)) value returned by mouse() reflects
this convention, returning 2 or 3 for those cases, even though
it is button 1 that is actually being pressed. Therefore, there
is no way to distinguish shift-left from shift-middle, because the
long(result(11)) mask indicates tht the shift button is pressed
in either case. (And on a machine without a middle button,
there would be no way to emulate shift-middle anyway.)
SEE ALSO: moush
DOCUMENT moush()
or moush(y, x, ireg)
returns the 1-origin zone index for the point clicked in
for the default mesh, or for the mesh (X,Y) (region array IREG).
DOCUMENT pause, milliseconds
or pause(milliseconds)
pause for the specified number of milliseconds of wall clock
time, or until input arrives from the keyboard.
If you call pause as a function, the return value is 1
if the specified number of milliseconds elapsed, or 0 if
keyboard input caused the pause to abort.
This is intended for use in creating animated sequences.
DOCUMENT rgb = rgb_read()
or rgb = rgb_read(n)
Read contents of current graphics window, or of graphics window N.
RGB is a 3xNXxNY array of char where NXxNY is the current shape of
the window in pixels. RGB(1,,) is the red component, RGB(2,,) is
the green component, and RGB(3,,) is the blue component, with 0
black and 255 full intensity. RGB(,,1) is the top row of the
window, RGB(,,2) the second row, and so on to RGB(,,0), which is
the bottom row. (So RGB(,,::-1) to pli redraws a copy.)