int main (int argc, const char * argv[]) {
uint32_t displayCount;
CGGetActiveDisplayList(0, NULL, &displayCount);
if (displayCount != 2) {
fprintf(stderr, "Error: expected exactly 2 displays, %d found\n", displayCount);
exit(1);
}
CGDirectDisplayID activeDisplays[displayCount];
CGGetActiveDisplayList(displayCount, activeDisplays, &displayCount);
const int32_t xTranslation = -CGRectGetMinX(CGDisplayBounds(activeDisplays[1]));
CGDisplayConfigRef config;
CGBeginDisplayConfiguration(&config);
CGConfigureDisplayFadeEffect(config, 0.2, 0.2, 0, 0, 0);
for (int i = 0; i < displayCount; ++i) {
CGDirectDisplayID display = activeDisplays[i];
CGRect displayBounds = CGDisplayBounds(display);
CGConfigureDisplayOrigin(config, display, CGRectGetMinX(displayBounds) + xTranslation, CGRectGetMinY(displayBounds));
}
CGCompleteDisplayConfiguration(config, kCGConfigurePermanently);
return 0;
}
void
setMainDisplay(CGDirectDisplayID targetDisplay)
{
int deltaX, deltaY, flag;
CGDisplayErr dErr;
CGDisplayCount displayCount, i;
CGDirectDisplayID mainDisplay;
CGDisplayCount maxDisplays = MAX_DISPLAYS;
CGDirectDisplayID onlineDisplays[MAX_DISPLAYS];
CGDisplayConfigRef config;
mainDisplay = CGMainDisplayID();
if (mainDisplay == targetDisplay) {
exit(0);
}
dErr = CGGetOnlineDisplayList(maxDisplays, onlineDisplays, &displayCount);
if (dErr != kCGErrorSuccess) {
fprintf(stderr, "CGGetOnlineDisplayList: error %d.\n", dErr);
exit(1);
}
flag = 0;
for (i = 0; i < displayCount; i++) {
CGDirectDisplayID dID = onlineDisplays[i];
if (dID == targetDisplay) { flag = 1; }
}
if (flag == 0) {
fprintf(stderr, "No such display ID: %10p.\n", targetDisplay);
exit(1);
}
deltaX = -CGRectGetMinX (CGDisplayBounds (targetDisplay));
deltaY = -CGRectGetMinY (CGDisplayBounds (targetDisplay));
CGBeginDisplayConfiguration (&config);
for (i = 0; i < displayCount; i++) {
CGDirectDisplayID dID = onlineDisplays[i];
CGConfigureDisplayOrigin (config, dID,
CGRectGetMinX (CGDisplayBounds (dID)) + deltaX,
CGRectGetMinY (CGDisplayBounds (dID)) + deltaY );
}
CGCompleteDisplayConfiguration (config, kCGConfigureForSession);
exit(0);
}
