main.c

// vim: ts=4:sw=4
/*
 * screenresolution sets the screen resolution on Mac computers.
 * Copyright (C) 2011  John Ford <john@johnford.info>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include "version.h"
#include "cg_utils.h"
#include <sys/param.h>
 
// Number of modes to list per line.
#define MODES_PER_LINE 3

// I have written an alternate list routine that spits out WAY more info
// #define LIST_DEBUG 1

unsigned int listAvailableModes(CGDirectDisplayID display, int displayNum);
unsigned int listCurrentMode(CGDirectDisplayID display, int displayNum);

int main(int argc, const char *argv[]) {
    // http://developer.apple.com/library/IOs/#documentation/CoreFoundation/Conceptual/CFStrings/Articles/MutableStrings.html
    int i;
    CFMutableStringRef args = CFStringCreateMutable(NULL, 0);
    CFStringEncoding encoding = CFStringGetSystemEncoding();
    CFStringAppend(args, CFSTR("starting screenresolution argv="));
    for (i = 0 ; i < argc ; i++) {
        CFStringAppendCString(args, argv[i], encoding);
        // If I were so motivated, I'd probably use CFStringAppendFormat
        CFStringAppend(args, CFSTR(" "));
    }
    // This has security implications.  Will look at that later
    NSLog(CFSTR("%@"), args);
    unsigned int exitcode = 0;

    if (argc > 1) {
        int d;
        int keepgoing = 1;
        CGError rc;
        uint32_t displayCount = 0;
        uint32_t activeDisplayCount = 0;
        CGDirectDisplayID *activeDisplays = NULL;

        rc = CGGetActiveDisplayList(0, NULL, &activeDisplayCount);
        if (rc != kCGErrorSuccess) {
            NSLog(CFSTR("%s"), "Error: failed to get list of active displays");
            return 1;
        }
        // Allocate storage for the next CGGetActiveDisplayList call
        activeDisplays = (CGDirectDisplayID *) malloc(activeDisplayCount * sizeof(CGDirectDisplayID));
        if (activeDisplays == NULL) {
            NSLog(CFSTR("%s"), "Error: could not allocate memory for display list");
            return 1;
        }
        rc = CGGetActiveDisplayList(activeDisplayCount, activeDisplays, &displayCount);
        if (rc != kCGErrorSuccess) {
            NSLog(CFSTR("%s"), "Error: failed to get list of active displays");
            return 1;
        }

        if (strcmp(argv[1], "help") == 0 || strcmp(argv[1], "-?") == 0) {
	    printf("There are three commands that this program supports: get, list and set.\n\
All three modes operate on active displays.\n\
\n\
The get mode will show you the resolution of all active displays\n\
\n\
    $ screenresolution get\n\
    Display 0: 1920x1200x32\n\
    Display 1: 1920x1200x32\n\
\n\
The list mode will show you to the available resolutions of all active\n\
displays, seperated by various whitespace.\n\
\n\
    Available Modes on Display 0\n\
      1920x1200x8   1920x1200x16    1920x1200x32    960x600x8\n\
      960x600x16    960x600x32      1680x1050x8     1680x1050x16\n\
    <snip>\n\
    Available Modes on Display 1\n\
    <snip>\n\
\n\
The set command takes a list of modes.  It will apply the modes\n\
in the list of modes to the list of displays, starting with 0.\n\
Modes in excess of the number of active displays will be ignored.\n\
If you wish to set a monitor but not the lower numbered displays,\n\
there is a keyword 'skip' which can be subsituted for a resolution.\n\
This keyword will cause the first display to be skipped.  If you\n\
specify more resolutions than you have active screens, the extra\n\
resolutions will be ignored.\n\
\n\
Example 1:\n\
    This example works with one or more screens\n\
    $ screenresolution set 800x600x32\n\
Result 1:\n\
    The main display will change to 800x600x32, second screen\n\
    will not be changed\n\
\n\
Example 2:\n\
    This example assumes two screens\n\
    $ screenresolution set 800x600x32 800x600x32\n\
Result 2:\n\
    The first and second monitor on the system will be set to\n\
    800x600x32\n\
\n\
Example 3:\n\
    This example assumes two screens\n\
    $ screen resolution set skip 800x600x32\n\
    This will not touch the first screen but will set the second\n\
    screen to 800x600x32\n");
	    return(0);
	}
        // This loop should probably be in another function.
        for (d = 0; d < displayCount && keepgoing; d++) {
            if (strcmp(argv[1], "get") == 0) {
                if (!listCurrentMode(activeDisplays[d], d)) {
                    exitcode++;
                }
            } else if (strcmp(argv[1], "list") == 0) {
                if (!listAvailableModes(activeDisplays[d], d)) {
                    exitcode++;
                }
            } else if (strcmp(argv[1], "set") == 0) {
                if (d < (argc - 2)) {
                    if (strcmp(argv[d+2], "skip") == 0 && d < (argc - 2)) {
                        printf("Skipping display %d\n", d);
                    } else {
                        struct config newConfig;
                        if (parseStringConfig(argv[d + 2], &newConfig)) {
                            if (!configureDisplay(activeDisplays[d], &newConfig, d)) {
                                exitcode++;
                            }
                        } else {
                            exitcode++;
                        }
                    }
                }
            } else if (strcmp(argv[1], "-version") == 0) {
                printf("screenresolution version %s\nLicensed under GPLv2\n", VERSION);
                keepgoing = 0;
            } else {
                NSLog(CFSTR("I'm sorry %s. I'm afraid I can't do that"), getlogin());
                exitcode++;
                keepgoing = 0;
            }
        }
        free(activeDisplays);
        activeDisplays = NULL;
    } else {
        NSLog(CFSTR("%s"), "Incorrect command line.\nUsage: screenresolution help|list|get|set <new resolution>");
        exitcode++;
    }
    return exitcode > 0;
}

unsigned int listCurrentMode(CGDirectDisplayID display, int displayNum) {
    unsigned int returncode = 1;
    CGDisplayModeRef currentMode = CGDisplayCopyDisplayMode(display);
    if (currentMode == NULL) {
        NSLog(CFSTR("%s"), "Error: unable to copy current display mode");
        returncode = 0;
    }
    NSLog(CFSTR("Display %d: %ux%ux%u@%.0f"),
           displayNum,
           CGDisplayModeGetWidth(currentMode),
           CGDisplayModeGetHeight(currentMode),
           bitDepth(currentMode),
           CGDisplayModeGetRefreshRate(currentMode));
    CGDisplayModeRelease(currentMode);
    return returncode;
}

unsigned int listAvailableModes(CGDirectDisplayID display, int displayNum) {
    unsigned int returncode = 1;
    int numModes = 0;
    int i;

    CFArrayRef allModes = CGDisplayCopyAllDisplayModes(display, NULL);
    if (allModes == NULL) {
        returncode = 0;
    }

    numModes = CFArrayGetCount(allModes);

    // sort the array of display modes
    CFMutableArrayRef allModesSorted =  CFArrayCreateMutableCopy(
                                          kCFAllocatorDefault,
                                          numModes,
                                          allModes
                                        );

    CFArraySortValues(
        allModesSorted,
        CFRangeMake(0, CFArrayGetCount(allModesSorted)),
        (CFComparatorFunction) _compareCFDisplayModes,
        NULL
    ); 

#ifndef LIST_DEBUG
    if(displayNum != 0)
        printf("\n\n");
    printf("Available Modes on Display %d\n", displayNum);
#endif

    CGDisplayModeRef mode;

    int modesPerColumn = numModes / MODES_PER_LINE;

    for (i = 0; (i < numModes) && returncode; i++) {
        int rowNumber = (i / MODES_PER_LINE);
        int idxDisplayMode = (i % MODES_PER_LINE) * modesPerColumn + rowNumber;

        // if there are an even number of display modes to display,
        // the last mode must have it's index decremented by 1
        idxDisplayMode = MIN(idxDisplayMode, numModes - 1);

        mode = (CGDisplayModeRef) CFArrayGetValueAtIndex(allModesSorted, idxDisplayMode);

        // This formatting is functional but it ought to be done less poorly.
#ifndef LIST_DEBUG
        if (i % MODES_PER_LINE == 0) {
            printf("  ");
        } else {
            printf("\t");
        }

        char modestr [50];
        sprintf(modestr, "%4lux%4lux%lu@%.0f",
               CGDisplayModeGetWidth(mode),
               CGDisplayModeGetHeight(mode),
               bitDepth(mode),
               CGDisplayModeGetRefreshRate(mode));
        printf("%-20s ", modestr);

        if(i % MODES_PER_LINE == MODES_PER_LINE - 1)
            printf("\n");
#else
        uint32_t ioflags = CGDisplayModeGetIOFlags(mode);
        printf("display: %d %4lux%4lux%2lu@%.0f usable:%u ioflags:%4x valid:%u safe:%u default:%u",
                displayNum,
                CGDisplayModeGetWidth(mode),
                CGDisplayModeGetHeight(mode),
                bitDepth(mode),
                CGDisplayModeGetRefreshRate(mode),
                CGDisplayModeIsUsableForDesktopGUI(mode),
                ioflags,
                ioflags & kDisplayModeValidFlag ?1:0,
                ioflags & kDisplayModeSafeFlag ?1:0,
                ioflags & kDisplayModeDefaultFlag ?1:0 );
        printf(" safety:%u alwaysshow:%u nevershow:%u notresize:%u requirepan:%u int:%u simul:%u",
                ioflags & kDisplayModeSafetyFlags ?1:0,
                ioflags & kDisplayModeAlwaysShowFlag ?1:0,
                ioflags & kDisplayModeNeverShowFlag ?1:0,
                ioflags & kDisplayModeNotResizeFlag ?1:0,
                ioflags & kDisplayModeRequiresPanFlag ?1:0,
                ioflags & kDisplayModeInterlacedFlag ?1:0,
                ioflags & kDisplayModeSimulscanFlag ?1:0 );
        printf(" builtin:%u notpreset:%u stretched:%u notgfxqual:%u valagnstdisp:%u tv:%u vldmirror:%u\n",
                ioflags & kDisplayModeBuiltInFlag ?1:0,
                ioflags & kDisplayModeNotPresetFlag ?1:0,
                ioflags & kDisplayModeStretchedFlag ?1:0,
                ioflags & kDisplayModeNotGraphicsQualityFlag ?1:0,
                ioflags & kDisplayModeValidateAgainstDisplay ?1:0,
                ioflags & kDisplayModeTelevisionFlag ?1:0,
                ioflags & kDisplayModeValidForMirroringFlag ?1:0 );
#endif
    }

    CFRelease(allModes);
    CFRelease(allModesSorted);

    return returncode;
}