Function pixel_format_comparator

platform/mac/pixelformat.cpp:642–784

static CFComparisonResult pixel_format_comparator(const void *val1, const void *val2, void *context)
{
    CFNumberRef number1 = (CFNumberRef)val1;
    CFNumberRef number2 = (CFNumberRef)val2;
    UInt64 code1, code2;
    pixel_format pf1, pf2;
    int category1, category2;

    CFNumberGetValue(number1, kCFNumberLongLongType, &code1);
    CFNumberGetValue(number2, kCFNumberLongLongType, &code2);
    pf1 = pixel_format_for_code(code1);
    pf2 = pixel_format_for_code(code2);
    category1 = pixel_format_category(pf1);
    category2 = pixel_format_category(pf2);

    if (category1 < category2) {
        return kCFCompareLessThan;
    }
    if (category1 > category2) {
        return kCFCompareGreaterThan;
    }
    /* Within a category, sort the "best" formats toward the front since that's
       what wglChoosePixelFormatARB() has to do.  The ordering implemented here
       matches at least one Windows 7 machine's behavior.
     */
    /* Accelerated before unaccelerated. */
    if (pf1.accelerated && !pf2.accelerated) {
        return kCFCompareLessThan;
    }
    if (!pf1.accelerated && pf2.accelerated) {
        return kCFCompareGreaterThan;
    }
    /* Explicit color mode ordering. */
    if (color_modes[pf1.color_mode].color_ordering < color_modes[pf2.color_mode].color_ordering) {
        return kCFCompareLessThan;
    }
    if (color_modes[pf1.color_mode].color_ordering > color_modes[pf2.color_mode].color_ordering) {
        return kCFCompareGreaterThan;
    }

    /* Non-pbuffer-capable before pbuffer-capable. */
    if (!pf1.pbuffer && pf2.pbuffer) {
        return kCFCompareLessThan;
    }
    if (pf1.pbuffer && !pf2.pbuffer) {
        return kCFCompareGreaterThan;
    }
    /* Fewer samples before more samples. */
    if (pf1.samples < pf2.samples) {
        return kCFCompareLessThan;
    }
    if (pf1.samples > pf2.samples) {
        return kCFCompareGreaterThan;
    }
    /* Monoscopic before stereoscopic.  (This is a guess.) */
    if (!pf1.stereo && pf2.stereo) {
        return kCFCompareLessThan;
    }