LIBXEARTH(3) LIBXEARTH(3)
February 11, 1999
NAME
Earth - The earth widget class
SYNOPSIS
#include <Earth.h>
extern void XearthSetViewMag(
Widget self,
float view_mag
);
extern void XearthSetViewRot(
Widget self,
float view_rot
);
extern void XearthSetViewLat(
Widget self,
float view_lat
);
extern void XearthSetViewLon(
Widget self,
float view_lon
);
extern void XearthChildGetLatitude(
Widget child,
float *latitude
);
extern void XearthChildGetLongitude(
Widget child,
float *longitude
);
extern void XearthChildSetLatitude(
Widget child,
float latitude
);
extern void XearthChildSetLongitude(
Widget child,
float longitude
);
extern int XearthGetXY(
Widget self,
float latitude,
float longitude,
Position *xret,
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LIBXEARTH(3) LIBXEARTH(3)
February 11, 1999
Position *yret
);
DESCRIPTION
Earth is the reentrant version of the well known xearth. Is is a
constraint widget ant manages visibility of its children according
their geographical positions.
XearthGetXY() returns 1 if position is visible, otherwise zero.
Resources
projType might be mercator or orthographic.
viewPosType might be fixed, sunrel, or orbit.
viewLat is the view latitude.
viewLon is the view longitude.
period is the orbital period.
inclin is the orbital inclination.
viewRot is the view rotation.
viewMag is the view magnification.
starFreq is the star frequency,
bigStars displays big stars.
day defines the day percentage.
night defines the night percentage.
terminator see xearth.
mono displays the earth in monochrome (even on color
displays).
numColors defines the number of colors used.
xGamma defines the xgamma of the display.
time defines the unix time (time_t) of the earth.
shiftX defines the horizontal shift.
shiftY defines the vertical shift.
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LIBXEARTH(3) LIBXEARTH(3)
February 11, 1999
computeSunPos computes the sun position.
doShade does a day/night rendering.
doStars displays stars instead of a dark space.
doGrid displays the position vertices.
gridBig displays a big grid.
gridSmall displays a small grid.
Constraint resources
latitude defines the latitude of the child.
longitude defines the longitude of the child.
NOTES TO IMPLEMENTORS
To make the code reentrant and to interface correctly with the code of
xearth (to respect the original code), We've had to create some kind
of structures (t_map_scan_input, t_map_scan_output, etc...). The
simplest thing is to understand well the meaning of these structures.
Be careful, when a Resize() occurs, we have to call the correct
reallocation methods because we've tried to limit them. By example,
when the resource XtNtime changes, we don't realloc the rendermap nor
the XImage (because XtNwidth and XtNheight hasn't changed).
Not all the resources are deeply implemented (but almost all the most
interesting ones). You have to know that there is some big problems
with XtRfloat!!! On a 32 bit system, you can't pass them trough a
XtSetValues and the best thing you've got to do (to be portable) is to
pass them in using XtRString (and by example XtVaTypedArg). There is
also another method by implementing public procedures (as in
XawScrollbar for the thumb resource). It's what it has been done.
SEE ALSO
xearth(1)
TODO
XearthDrawLine() to draw lines on the earth surface. We have to find a
way to keep a context concerning these lines to correctly redraw them
on exposures.
AUTHORS
Kirk Lauritz Johnson <tuna@cag.lcs.mit.edu> - original author of
xearth. Martin Gall (mgall@capmedia.fr) - widget version.
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