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Tk_GetPixels, Tk_GetScreenMM ? translate between strings and screen units |
#include <tk.h> int Tk_GetPixels(interp, tkwin, string, intPtr) int Tk_GetScreenMM(interp, tkwin, string, doublePtr) |
Tcl_Interp *interp (in)
Interpreter to use for error reporting.
Tk_Window tkwin (in)
Window whose screen geometry determines the conversion between absolute units and pixels.
char *string (in)
String that specifies a distance on the screen.
int *intPtr (out)
Pointer to location in which to store converted distance in pixels.
double *doublePtr (out)
Pointer to location in which to store converted distance in millimeters.
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These two procedures take as argument a specification of distance on the screen (string) and compute the corresponding distance either in integer pixels or floating-point millimeters. In either case, string specifies a screen distance as a floating-point number followed by one of the following characters that indicates units: |
<none> |
The number specifies a distance in pixels. |
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c |
The number specifies a distance in centimeters on the screen. |
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i |
The number specifies a distance in inches on the screen. |
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m |
The number specifies a distance in millimeters on the screen. |
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p |
The number specifies a distance in printer’s points (1/72 inch) on the screen. |
Tk_GetPixels converts string to the nearest even number of pixels and stores that value at *intPtr. Tk_GetScreenMM converts string to millimeters and stores the double-precision floating-point result at *doublePtr. Both procedures return TCL_OK under normal circumstances. If an error occurs (e.g. string contains a number followed by a character that isn’t one of the ones above) then TCL_ERROR is returned and an error message is left in interp->result. |
centimeters, convert, inches, millimeters, pixels, points, screen units |