6cddd69891
mirror_displays() now checks CGDisplayMirrorsDisplay() for each secondary before calling CGBeginDisplayConfiguration — avoids a needless display reconfiguration (and potential flicker) when already mirrored. extend_displays() already had this check; no change needed there.
378 lines
15 KiB
Objective-C
378 lines
15 KiB
Objective-C
/*
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* display_control.m
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* Native macOS CLI for programmatic display mirror/extend control.
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*
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* Derived from the OSIT MasterKey app (LegacyUtilities.m, Ian Kohl 2019).
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* Uses CoreGraphics APIs — no external dependencies (no displayplacer/Homebrew required).
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*
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* Build: run scripts/build-display-control.sh on a Mac (requires Xcode Command Line Tools)
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* Usage: display_control <mirror|extend|status>
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*/
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#import <Cocoa/Cocoa.h>
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#include <Carbon/Carbon.h>
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#include <math.h>
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#define MAX_DISPLAYS 8
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#define MAX_MODES 256
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typedef struct { long src_index; size_t w, h, pw, ph; double refresh; } ModeEntry;
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static int mirror_displays(void) {
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CGDirectDisplayID onlineDspys[MAX_DISPLAYS] = {0};
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CGDisplayCount numOnline = 0;
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CGGetOnlineDisplayList(MAX_DISPLAYS, onlineDspys, &numOnline);
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if (numOnline < 2) {
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fprintf(stderr, "No secondary display detected (%u online).\n", numOnline);
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return 1;
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}
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CGDirectDisplayID mainID = CGMainDisplayID();
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// Idempotency: if every secondary is already mirroring mainID, nothing to do.
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CGDisplayCount alreadyMirrored = 0;
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for (CGDisplayCount i = 0; i < numOnline; i++) {
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if (onlineDspys[i] != mainID && CGDisplayMirrorsDisplay(onlineDspys[i]) == mainID)
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alreadyMirrored++;
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}
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if (alreadyMirrored == numOnline - 1) {
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printf("Displays already mirrored.\n");
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return 0;
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}
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CGDisplayConfigRef config;
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CGError err = CGBeginDisplayConfiguration(&config);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGBeginDisplayConfiguration failed: %d\n", err);
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return 1;
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}
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BOOL any_configured = NO;
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for (CGDisplayCount i = 0; i < numOnline; i++) {
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if (onlineDspys[i] != mainID) {
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err = CGConfigureDisplayMirrorOfDisplay(config, onlineDspys[i], mainID);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGConfigureDisplayMirrorOfDisplay failed: %d\n", err);
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CGCancelDisplayConfiguration(config);
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return 1;
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}
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any_configured = YES;
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}
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}
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if (!any_configured) {
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CGCancelDisplayConfiguration(config);
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fprintf(stderr, "No secondary displays to mirror.\n");
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return 1;
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}
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err = CGCompleteDisplayConfiguration(config, kCGConfigurePermanently);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGCompleteDisplayConfiguration failed: %d\n", err);
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return 1;
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}
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printf("Mirrored %u display(s).\n", numOnline - 1);
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return 0;
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}
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static int extend_displays(void) {
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CGDirectDisplayID onlineDspys[MAX_DISPLAYS] = {0};
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CGDirectDisplayID activeDspys[MAX_DISPLAYS] = {0};
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CGDisplayCount numOnline = 0, numActive = 0;
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CGGetOnlineDisplayList(MAX_DISPLAYS, onlineDspys, &numOnline);
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CGGetActiveDisplayList(MAX_DISPLAYS, activeDspys, &numActive);
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if (numOnline < 2) {
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fprintf(stderr, "No secondary display detected (%u online).\n", numOnline);
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return 1;
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}
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if (numActive >= numOnline) {
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printf("Displays already extended.\n");
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return 0;
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}
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CGDirectDisplayID mainID = CGMainDisplayID();
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CGDisplayConfigRef config;
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CGError err = CGBeginDisplayConfiguration(&config);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGBeginDisplayConfiguration failed: %d\n", err);
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return 1;
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}
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for (CGDisplayCount i = 0; i < numOnline; i++) {
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if (onlineDspys[i] != mainID) {
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// kCGNullDirectDisplay as master = un-mirror (extend)
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err = CGConfigureDisplayMirrorOfDisplay(config, onlineDspys[i], kCGNullDirectDisplay);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGConfigureDisplayMirrorOfDisplay(null) failed: %d\n", err);
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CGCancelDisplayConfiguration(config);
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return 1;
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}
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}
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}
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err = CGCompleteDisplayConfiguration(config, kCGConfigurePermanently);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGCompleteDisplayConfiguration failed: %d\n", err);
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return 1;
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}
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printf("Displays extended.\n");
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return 0;
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}
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static void print_status(void) {
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CGDirectDisplayID onlineDspys[MAX_DISPLAYS] = {0};
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CGDirectDisplayID activeDspys[MAX_DISPLAYS] = {0};
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CGDisplayCount numOnline = 0, numActive = 0;
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CGGetOnlineDisplayList(MAX_DISPLAYS, onlineDspys, &numOnline);
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CGGetActiveDisplayList(MAX_DISPLAYS, activeDspys, &numActive);
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printf("online=%u active=%u %s\n",
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numOnline, numActive,
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(numOnline > 1 && numActive < numOnline) ? "mirrored" : "extended");
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}
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// ── list-modes ──────────────────────────────────────────────────────────────
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// Outputs a JSON array describing every online display and its available modes.
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static void list_modes(void) {
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CGDirectDisplayID displays[MAX_DISPLAYS];
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CGDisplayCount count = 0;
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CGGetOnlineDisplayList(MAX_DISPLAYS, displays, &count);
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CGDirectDisplayID mainID = CGMainDisplayID();
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printf("[\n");
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for (CGDisplayCount d = 0; d < count; d++) {
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CGDirectDisplayID dID = displays[d];
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CGDisplayModeRef currentMode = CGDisplayCopyDisplayMode(dID);
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size_t curW = CGDisplayModeGetWidth(currentMode);
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size_t curH = CGDisplayModeGetHeight(currentMode);
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double curR = CGDisplayModeGetRefreshRate(currentMode);
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size_t curPW = CGDisplayModeGetPixelWidth(currentMode);
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size_t curPH = CGDisplayModeGetPixelHeight(currentMode);
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// Include HiDPI duplicate entries so scaled modes are visible.
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CFStringRef optKeys[] = { kCGDisplayShowDuplicateLowResolutionModes };
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CFBooleanRef optVals[] = { kCFBooleanTrue };
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CFDictionaryRef opts = CFDictionaryCreate(NULL,
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(const void **)optKeys, (const void **)optVals, 1,
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&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
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CFArrayRef allModes = CGDisplayCopyAllDisplayModes(dID, opts);
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CFRelease(opts);
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CFIndex total = CFArrayGetCount(allModes);
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// Collect usable modes first so we know the count for comma handling.
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ModeEntry usable[MAX_MODES];
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int usable_count = 0;
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for (CFIndex m = 0; m < total && usable_count < MAX_MODES; m++) {
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CGDisplayModeRef mode = (CGDisplayModeRef)CFArrayGetValueAtIndex(allModes, m);
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if (!CGDisplayModeIsUsableForDesktopGUI(mode)) continue;
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usable[usable_count++] = (ModeEntry){
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.src_index = (long)m,
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.w = CGDisplayModeGetWidth(mode),
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.h = CGDisplayModeGetHeight(mode),
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.pw = CGDisplayModeGetPixelWidth(mode),
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.ph = CGDisplayModeGetPixelHeight(mode),
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.refresh = CGDisplayModeGetRefreshRate(mode)
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};
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}
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printf(" {\n");
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printf(" \"index\": %u,\n", d);
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printf(" \"id\": %u,\n", (unsigned int)dID);
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printf(" \"is_main\": %s,\n", dID == mainID ? "true" : "false");
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printf(" \"current_width\": %zu,\n", curW);
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printf(" \"current_height\": %zu,\n", curH);
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printf(" \"current_refresh\": %.2f,\n", curR);
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printf(" \"current_pixel_width\": %zu,\n", curPW);
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printf(" \"current_pixel_height\": %zu,\n", curPH);
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printf(" \"modes\": [\n");
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for (int i = 0; i < usable_count; i++) {
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ModeEntry *e = &usable[i];
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int isCurrent = (e->w == curW && e->h == curH &&
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e->pw == curPW && e->ph == curPH &&
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fabs(e->refresh - curR) < 0.5);
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printf(" {\"index\":%ld,\"width\":%zu,\"height\":%zu,"
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"\"refresh\":%.2f,\"pixel_width\":%zu,\"pixel_height\":%zu,"
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"\"hidpi\":%s,\"is_current\":%s}%s\n",
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e->src_index, e->w, e->h, e->refresh, e->pw, e->ph,
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(e->pw > e->w || e->ph > e->h) ? "true" : "false",
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isCurrent ? "true" : "false",
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(i < usable_count - 1) ? "," : "");
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}
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printf(" ]\n");
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printf(" }%s\n", (d < count - 1) ? "," : "");
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CGDisplayModeRelease(currentMode);
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CFRelease(allModes);
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}
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printf("]\n");
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}
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// ── set-mode ─────────────────────────────────────────────────────────────────
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// display_idx : index from list-modes (0 = primary, 1 = first external, ...)
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// req_w/h : logical width × height (what macOS calls "looks like X×Y")
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// req_refresh : 0 = pick highest available; >0 = must be within 1 Hz
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// force_hidpi : 1 = HiDPI only; -1 = non-HiDPI only; 0 = auto
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// auto prefers HiDPI on the built-in, non-HiDPI on externals
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static int set_mode(int display_idx, size_t req_w, size_t req_h,
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double req_refresh, int force_hidpi) {
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CGDirectDisplayID displays[MAX_DISPLAYS];
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CGDisplayCount count = 0;
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CGGetOnlineDisplayList(MAX_DISPLAYS, displays, &count);
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if (display_idx < 0 || (CGDisplayCount)display_idx >= count) {
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fprintf(stderr, "Display index %d out of range (0..%u).\n",
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display_idx, count > 0 ? count - 1 : 0);
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return 1;
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}
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CGDirectDisplayID dID = displays[display_idx];
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int isMain = (dID == CGMainDisplayID());
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CFStringRef optKeys[] = { kCGDisplayShowDuplicateLowResolutionModes };
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CFBooleanRef optVals[] = { kCFBooleanTrue };
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CFDictionaryRef opts = CFDictionaryCreate(NULL,
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(const void **)optKeys, (const void **)optVals, 1,
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&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
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CFArrayRef allModes = CGDisplayCopyAllDisplayModes(dID, opts);
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CFRelease(opts);
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CFIndex total = CFArrayGetCount(allModes);
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CGDisplayModeRef bestMode = NULL;
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double bestRefresh = -1.0;
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int bestScore = -1; // higher = more preferred
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for (CFIndex m = 0; m < total; m++) {
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CGDisplayModeRef mode = (CGDisplayModeRef)CFArrayGetValueAtIndex(allModes, m);
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if (!CGDisplayModeIsUsableForDesktopGUI(mode)) continue;
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size_t w = CGDisplayModeGetWidth(mode);
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size_t h = CGDisplayModeGetHeight(mode);
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if (w != req_w || h != req_h) continue;
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double refresh = CGDisplayModeGetRefreshRate(mode);
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if (req_refresh > 0.0 && fabs(refresh - req_refresh) > 1.0) continue;
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size_t pw = CGDisplayModeGetPixelWidth(mode);
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int isHiDPI = (pw > w);
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if (force_hidpi == 1 && !isHiDPI) continue;
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if (force_hidpi == -1 && isHiDPI) continue;
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// Score: prefer HiDPI on main display, non-HiDPI on external.
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int score = (force_hidpi == 0)
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? ((isMain && isHiDPI) || (!isMain && !isHiDPI)) ? 1 : 0
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: 0;
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if (bestMode == NULL || score > bestScore ||
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(score == bestScore && refresh > bestRefresh)) {
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bestMode = mode;
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bestRefresh = refresh;
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bestScore = score;
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}
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}
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if (!bestMode) {
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fprintf(stderr, "No matching mode for display %d: %zux%zu",
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display_idx, req_w, req_h);
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if (req_refresh > 0.0) fprintf(stderr, " @%.0fHz", req_refresh);
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if (force_hidpi == 1) fprintf(stderr, " [HiDPI required]");
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if (force_hidpi == -1) fprintf(stderr, " [non-HiDPI required]");
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fprintf(stderr, ".\nRun: display_control list-modes\n");
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CFRelease(allModes);
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return 1;
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}
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size_t setW = CGDisplayModeGetWidth(bestMode);
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size_t setH = CGDisplayModeGetHeight(bestMode);
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double setR = CGDisplayModeGetRefreshRate(bestMode);
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size_t setPW = CGDisplayModeGetPixelWidth(bestMode);
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size_t setPH = CGDisplayModeGetPixelHeight(bestMode);
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CGDisplayConfigRef config;
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CGError err = CGBeginDisplayConfiguration(&config);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGBeginDisplayConfiguration failed: %d\n", err);
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CFRelease(allModes);
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return 1;
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}
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err = CGConfigureDisplayWithDisplayMode(config, dID, bestMode, NULL);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGConfigureDisplayWithDisplayMode failed: %d\n", err);
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CGCancelDisplayConfiguration(config);
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CFRelease(allModes);
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return 1;
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}
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err = CGCompleteDisplayConfiguration(config, kCGConfigurePermanently);
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if (err != kCGErrorSuccess) {
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fprintf(stderr, "CGCompleteDisplayConfiguration failed: %d\n", err);
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CFRelease(allModes);
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return 1;
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}
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printf("Set display %d to %zux%zu @%.0fHz (pixel %zux%zu).\n",
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display_idx, setW, setH, setR, setPW, setPH);
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CFRelease(allModes);
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return 0;
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}
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// ── main ─────────────────────────────────────────────────────────────────────
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int main(int argc, const char * argv[]) {
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@autoreleasepool {
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if (argc < 2) {
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fprintf(stderr, "Usage: display_control <mirror|extend|status|list-modes|set-mode>\n");
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return 1;
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}
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const char *cmd = argv[1];
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if (strcmp(cmd, "mirror") == 0) {
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return mirror_displays();
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} else if (strcmp(cmd, "extend") == 0) {
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return extend_displays();
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} else if (strcmp(cmd, "status") == 0) {
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print_status();
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return 0;
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} else if (strcmp(cmd, "list-modes") == 0) {
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list_modes();
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return 0;
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} else if (strcmp(cmd, "set-mode") == 0) {
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if (argc < 5) {
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fprintf(stderr, "Usage: display_control set-mode <display_index> <width> <height> [--refresh <hz>] [--hidpi] [--no-hidpi]\n");
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return 1;
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}
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int display_idx = atoi(argv[2]);
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size_t req_w = (size_t)atol(argv[3]);
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size_t req_h = (size_t)atol(argv[4]);
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double req_refresh = 0.0;
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int force_hidpi = 0;
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for (int i = 5; i < argc; i++) {
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if (strcmp(argv[i], "--refresh") == 0 && i + 1 < argc) {
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req_refresh = atof(argv[++i]);
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} else if (strcmp(argv[i], "--hidpi") == 0) {
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force_hidpi = 1;
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} else if (strcmp(argv[i], "--no-hidpi") == 0) {
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force_hidpi = -1;
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}
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}
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return set_mode(display_idx, req_w, req_h, req_refresh, force_hidpi);
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} else {
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fprintf(stderr, "Unknown command: %s\nUsage: display_control <mirror|extend|status|list-modes|set-mode>\n", cmd);
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return 1;
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}
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}
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}
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