mirror of https://github.com/cc65/cc65.git
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
/*
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** Main lightpen driver calibration functions.
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**
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** 2013-07-25, Greg King
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*/
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#include <stddef.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <pen.h>
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static const char *name;
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/* Get a lightpen calibration value from a file if it exists. Otherwise, call
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** pen_calibrate() to create a value; then, write it into a file, so that it
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** will be available at the next time that the lightpen is used.
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** Might change the screen.
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*/
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static void __fastcall__ adjuster (unsigned char *XOffset)
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{
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int fd = open (name, O_RDONLY);
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if (fd < 0) {
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pen_calibrate (XOffset);
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fd = open (name, O_WRONLY | O_CREAT | O_EXCL);
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if (fd >= 0) {
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(void) write (fd, XOffset, 1);
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close (fd);
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}
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} else {
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(void) read (fd, XOffset, 1);
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close (fd);
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}
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}
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/* pen_adjust() is optional; if you want to use its feature,
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** then it must be called before a driver is installed.
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** Note: This function merely saves the file-name pointer, and sets
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** the pen_adjuster pointer. The file will be read only when a driver
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** is installed, and only if that driver wants to be calibrated.
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*/
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void __fastcall__ pen_adjust (const char *filename)
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{
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if (filename != NULL && filename[0] != '\0') {
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name = filename;
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pen_adjuster = adjuster;
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} else {
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pen_adjuster = pen_calibrate;
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}
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}
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