如何在Mac OS X中更改屏幕亮度？

Question

我正在使用Safari插件（目標c）。 我想從插件更改屏幕亮度。 我已經嘗試過使用“ IODisplayGetFloatParameter”和“ IODisplaySetFloatParameter”。 但這給了我錯誤“無法獲得顯示0x1b5098cc的亮度（錯誤-536870201）”。 如何解決這個錯誤？

Answer 1

這是線程調整Mac顯示器亮度Objective-C的答案。

// almost completely from: http://mattdanger.net/2008/12/adjust-mac-os-x-display-brightness-from-the-terminal/
- (float) get_brightness {
    CGDirectDisplayID display[kMaxDisplays];
    CGDisplayCount numDisplays;
    CGDisplayErr err;
    err = CGGetActiveDisplayList(kMaxDisplays, display, &numDisplays);

    if (err != CGDisplayNoErr)
        printf("cannot get list of displays (error %d)\n",err);
    for (CGDisplayCount i = 0; i < numDisplays; ++i) {


        CGDirectDisplayID dspy = display[i];
        CFDictionaryRef originalMode = CGDisplayCurrentMode(dspy);
        if (originalMode == NULL)
            continue;
        io_service_t service = CGDisplayIOServicePort(dspy);

        float brightness;
        err= IODisplayGetFloatParameter(service, kNilOptions, kDisplayBrightness,
                                        &brightness);
        if (err != kIOReturnSuccess) {
            fprintf(stderr,
                    "failed to get brightness of display 0x%x (error %d)",
                    (unsigned int)dspy, err);
            continue;
        }
        return brightness;
    }       
    return -1.0;//couldn't get brightness for any display
}


// almost completely from: http://mattdanger.net/2008/12/adjust-mac-os-x-display-brightness-from-the-terminal/
- (void) set_brightness:(float) new_brightness {
    CGDirectDisplayID display[kMaxDisplays];
    CGDisplayCount numDisplays;
    CGDisplayErr err;
    err = CGGetActiveDisplayList(kMaxDisplays, display, &numDisplays);

    if (err != CGDisplayNoErr)
        printf("cannot get list of displays (error %d)\n",err);
    for (CGDisplayCount i = 0; i < numDisplays; ++i) {


        CGDirectDisplayID dspy = display[i];
        CFDictionaryRef originalMode = CGDisplayCurrentMode(dspy);
        if (originalMode == NULL)
            continue;
                io_service_t service = CGDisplayIOServicePort(dspy);

        float brightness;
        err= IODisplayGetFloatParameter(service, kNilOptions, kDisplayBrightness,
                                        &brightness);
        if (err != kIOReturnSuccess) {
            fprintf(stderr,
                    "failed to get brightness of display 0x%x (error %d)",
                    (unsigned int)dspy, err);
            continue;
        }

        err = IODisplaySetFloatParameter(service, kNilOptions, kDisplayBrightness,
                                         new_brightness);
        if (err != kIOReturnSuccess) {
            fprintf(stderr,
                    "Failed to set brightness of display 0x%x (error %d)",
                     (unsigned int)dspy, err);
            continue;
        }

        if(brightness > 0.0){
        }else{
        }
    }       

}