qcolormap_x11.cpp

奇趣公司比较新的qt/emd版本

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#include "qcolormap.h"

#include "qapplication.h"
#include "qdebug.h"
#include "qdesktopwidget.h"
#include "qvarlengtharray.h"

#include "qx11info_x11.h"
#include <private/qt_x11_p.h>
#include <limits.h>

class QColormapPrivate
{
public:
    QColormapPrivate()
        : ref(1), mode(QColormap::Direct), depth(0),
          colormap(0), defaultColormap(true),
          visual(0), defaultVisual(true),
          r_max(0), g_max(0), b_max(0),
          r_shift(0), g_shift(0), b_shift(0)
    {}

    QAtomic ref;

    QColormap::Mode mode;
    int depth;

    Colormap colormap;
    bool defaultColormap;

    Visual *visual;
    bool defaultVisual;

    int r_max;
    int g_max;
    int b_max;

    uint r_shift;
    uint g_shift;
    uint b_shift;

    QVector<QColor> colors;
    QVector<int> pixels;
};


static uint right_align(uint v)
{
    while (!(v & 0x1))
        v >>= 1;
    return v;
}

static int lowest_bit(uint v)
{
    int i;
    uint b = 1u;
    for (i = 0; ((v & b) == 0u) && i < 32;  ++i)
        b <<= 1u;
    return i == 32 ? -1 : i;
}

static int cube_root(int v)
{
    if (v == 1)
        return 1;
    // brute force algorithm
    int i = 1;
    for (;;) {
        const int b = i * i * i;
        if (b <= v) {
            ++i;
        } else {
            --i;
            break;
        }
    }
    return i;
}

static Visual *find_visual(Display *display,
                           int screen,
                           int visual_class,
                           int visual_id,
                           int *depth,
                           bool *defaultVisual)
{
    XVisualInfo *vi, rvi;
    int count;

    uint mask = VisualScreenMask;
    rvi.screen = screen;

    if (visual_class != -1) {
        rvi.c_class = visual_class;
        mask |= VisualClassMask;
    }
    if (visual_id != -1) {
        rvi.visualid = visual_id;
        mask |= VisualIDMask;
    }

    Visual *visual = DefaultVisual(display, screen);
    *defaultVisual = true;
    *depth = DefaultDepth(display, screen);

    vi = XGetVisualInfo(display, mask, &rvi, &count);
    if (vi) {
        int best = 0;
        for (int x = 0; x < count; ++x) {
            if (vi[x].depth > vi[best].depth)
                best = x;
        }
        if (best >= 0 && best <= count && vi[best].visualid != XVisualIDFromVisual(visual)) {
            visual = vi[best].visual;
            *defaultVisual = (visual == DefaultVisual(display, screen));
            *depth = vi[best].depth;
        }
    }
    if (vi)
        XFree((char *)vi);
    return visual;
}

static void query_colormap(QColormapPrivate *d, int screen)
{
    Display *display = QX11Info::display();

    // query existing colormap
    int q_colors = (((1u << d->depth) > 256u) ? 256u : (1u << d->depth));
    XColor queried[256];
    memset(queried, 0, sizeof(queried));
    for (int x = 0; x < q_colors; ++x)
        queried[x].pixel = x;
    XQueryColors(display, d->colormap, queried, q_colors);

    d->colors.resize(q_colors);
    for (int x = 0; x < q_colors; ++x) {
        if (queried[x].red == 0
            && queried[x].green == 0
            && queried[x].blue == 0
            && queried[x].pixel != BlackPixel(display, screen)) {
            // unallocated color cell, skip it
            continue;
        }

        d->colors[x] = QColor::fromRgbF(queried[x].red / float(USHRT_MAX),
                                        queried[x].green / float(USHRT_MAX),
                                        queried[x].blue / float(USHRT_MAX));
    }

    // for missing colors, find the closest color in the existing colormap
    Q_ASSERT(d->pixels.size());
    for (int x = 0; x < d->pixels.size(); ++x) {
        if (d->pixels.at(x) != -1)
            continue;

        QRgb rgb;
        if (d->mode == QColormap::Indexed) {
            const int r = (x / (d->g_max * d->b_max)) % d->r_max;
            const int g = (x / d->b_max) % d->g_max;
            const int b = x % d->b_max;
            rgb = qRgb((r * 0xff + (d->r_max - 1) / 2) / (d->r_max - 1),
                       (g * 0xff + (d->g_max - 1) / 2) / (d->g_max - 1),
                       (b * 0xff + (d->b_max - 1) / 2) / (d->b_max - 1));
        } else {
            rgb = qRgb(x, x, x);
        }

        // find closest color
        int mindist = INT_MAX, best = -1;
        for (int y = 0; y < q_colors; ++y) {
            int r =   qRed(rgb) - (queried[y].red   >> 8);
            int g = qGreen(rgb) - (queried[y].green >> 8);
            int b =  qBlue(rgb) - (queried[y].blue  >> 8);
            int dist = (r * r) + (g * g) + (b * b);
            if (dist < mindist) {
                mindist = dist;
                best = y;
            }
        }

        Q_ASSERT(best >= 0 && best < q_colors);
        if (d->visual->c_class & 1) {
            XColor xcolor;
            xcolor.red   = queried[best].red;
            xcolor.green = queried[best].green;
            xcolor.blue  = queried[best].blue;
            xcolor.pixel = queried[best].pixel;

            if (XAllocColor(display, d->colormap, &xcolor)) {
                d->pixels[x] = xcolor.pixel;
            } else {
                // some weird stuff is going on...
                d->pixels[x] = (qGray(rgb) < 127
                                ? BlackPixel(display, screen)
                                : WhitePixel(display, screen));
            }
        } else {
            d->pixels[x] = best;
        }
    }
}

static void init_gray(QColormapPrivate *d, int screen)
{
    d->pixels.resize(d->r_max);

    for (int g = 0; g < d->g_max; ++g) {
        const int gray = (g * 0xff + (d->r_max - 1) / 2) / (d->r_max - 1);
        const QRgb rgb = qRgb(gray, gray, gray);

        d->pixels[g] = -1;

        if (d->visual->c_class & 1) {
            XColor xcolor;
            xcolor.red   =   qRed(rgb) * 0x101;
            xcolor.green = qGreen(rgb) * 0x101;
            xcolor.blue  =  qBlue(rgb) * 0x101;
            xcolor.pixel = 0ul;

            if (XAllocColor(QX11Info::display(), d->colormap, &xcolor))
                d->pixels[g] = xcolor.pixel;
        }
    }

    query_colormap(d, screen);
}

static void init_indexed(QColormapPrivate *d, int screen)
{
    d->pixels.resize(d->r_max * d->g_max * d->b_max);

    // create color cube
    for (int x = 0, r = 0; r < d->r_max; ++r) {
        for (int g = 0; g < d->g_max; ++g) {
            for (int b = 0; b < d->b_max; ++b, ++x) {
                const QRgb rgb = qRgb((r * 0xff + (d->r_max - 1) / 2) / (d->r_max - 1),
                                      (g * 0xff + (d->g_max - 1) / 2) / (d->g_max - 1),
                                      (b * 0xff + (d->b_max - 1) / 2) / (d->b_max - 1));

                d->pixels[x] = -1;

                if (d->visual->c_class & 1) {
                    XColor xcolor;
                    xcolor.red   =   qRed(rgb) * 0x101;
                    xcolor.green = qGreen(rgb) * 0x101;
                    xcolor.blue  =  qBlue(rgb) * 0x101;
                    xcolor.pixel = 0ul;

                    if (XAllocColor(QX11Info::display(), d->colormap, &xcolor))
                        d->pixels[x] = xcolor.pixel;
                }
            }
        }
    }

    query_colormap(d, screen);
}

static void init_direct(QColormapPrivate *d, bool ownColormap)
{
    if (d->visual->c_class != DirectColor || !ownColormap)
        return;

    // preallocate 768 on the stack, so that we don't have to malloc
    // for the common case (<= 24 bpp)
    QVarLengthArray<XColor, 768> colorTable(d->r_max + d->g_max + d->b_max);
    int i = 0;

    for (int r = 0; r < d->r_max; ++r) {
        colorTable[i].red = r << 8 | r;
        colorTable[i].pixel = r << d->r_shift;
        colorTable[i].flags = DoRed;
        ++i;
    }

    for (int g = 0; g < d->g_max; ++g) {
        colorTable[i].green = g << 8 | g;
        colorTable[i].pixel = g << d->g_shift;
        colorTable[i].flags = DoGreen;
        ++i;
    }

    for (int b = 0; b < d->b_max; ++b) {
        colorTable[i].blue = (b << 8 | b);
        colorTable[i].pixel = b << d->b_shift;
        colorTable[i].flags = DoBlue;
        ++i;
    }

    XStoreColors(X11->display, d->colormap, colorTable.data(), colorTable.count());
}

/*!
    \class QColormap
    \ingroup multimedia

    \brief The QColormap class maps device independent QColors to device dependent pixel values.
*/

/*! \enum QColormap::Mode

    This enum describes how QColormap maps device independent RGB
    values to device dependent pixel values.

    \value Direct Pixel values are derived directly from the RGB
    values, also known as "True Color."

    \value Indexed Pixel values represent indexes into a vector of
    available colors, i.e. QColormap uses the index of the color that
    most closely matches an RGB value.

    \value Gray Similar to \c Indexed, pixel values represent a vector
    of available gray tones.  QColormap uses the index of the gray
    tone that most closely matches the computed gray tone of an RGB
    value.
*/

static QColormap **cmaps = 0;

/*! \internal
*/
void QColormap::initialize()
{