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#include "qeglfshooks.h"
#include "qeglfscursor.h"

#include <fcntl.h>
#include <unistd.h>
#include <linux/fb.h>
#include <sys/ioctl.h>

#include <private/qmath_p.h>
#include <private/qcore_unix_p.h>

QT_BEGIN_NAMESPACE

// file descriptor for the frame buffer
// this is a global static to keep the QEglFSHooks interface as clean as possible
static int framebuffer = -1;

const char *QEglFSHooks::fbDeviceName() const
{
    return "/dev/fb0";
}

void QEglFSHooks::platformInit()
{
    framebuffer = qt_safe_open(fbDeviceName(), O_RDONLY);

    if (framebuffer == -1)
        qWarning("EGLFS: Failed to open %s", fbDeviceName());
}

void QEglFSHooks::platformDestroy()
{
    if (framebuffer != -1)
        close(framebuffer);
}

EGLNativeDisplayType QEglFSHooks::platformDisplay() const
{
    return EGL_DEFAULT_DISPLAY;
}

QSizeF QEglFSHooks::physicalScreenSize() const
{
    static QSizeF size;
    if (size.isEmpty()) {

        // Note: in millimeters
        int width = qgetenv("QT_QPA_EGLFS_PHYSICAL_WIDTH").toInt();
        int height = qgetenv("QT_QPA_EGLFS_PHYSICAL_HEIGHT").toInt();

        if (width && height) {
            // no need to read fb0
            size.setWidth(width);
            size.setHeight(height);
            return size;
        }

        struct fb_var_screeninfo vinfo;
        int w = -1;
        int h = -1;
        QSize screenResolution;

        if (framebuffer != -1) {
            if (ioctl(framebuffer, FBIOGET_VSCREENINFO, &vinfo) == -1) {
                qWarning("EGLFS: Could not query variable screen info.");
            } else {
                w = vinfo.width;
                h = vinfo.height;
                screenResolution = QSize(vinfo.xres, vinfo.yres);
            }
        } else {
            screenResolution = screenSize();
        }

        const int defaultPhysicalDpi = 100;
        size.setWidth(w <= 0 ? screenResolution.width() * Q_MM_PER_INCH / defaultPhysicalDpi : qreal(w));
        size.setHeight(h <= 0 ? screenResolution.height() * Q_MM_PER_INCH / defaultPhysicalDpi : qreal(h));

        if (w <= 0 || h <= 0) {
            qWarning("EGLFS: Unable to query physical screen size, defaulting to %d dpi.\n"
                     "EGLFS: To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH "
                     "and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).",
                     defaultPhysicalDpi);
        }

        // override fb0 from environment var setting
        if (width)
            size.setWidth(width);
        if (height)
            size.setWidth(height);
    }
    return size;
}

QSize QEglFSHooks::screenSize() const
{
    static QSize size;

    if (size.isEmpty()) {
        int width = qgetenv("QT_QPA_EGLFS_WIDTH").toInt();
        int height = qgetenv("QT_QPA_EGLFS_HEIGHT").toInt();

        if (width && height) {
            // no need to read fb0
            size.setWidth(width);
            size.setHeight(height);
            return size;
        }

        struct fb_var_screeninfo vinfo;

        int xres = -1;
        int yres = -1;

        if (framebuffer != -1) {
            if (ioctl(framebuffer, FBIOGET_VSCREENINFO, &vinfo) == -1) {
                qWarning("EGLFS: Could not query variable screen info.");
            } else {
                xres = vinfo.xres;
                yres = vinfo.yres;
            }
        }

        const int defaultWidth = 800;
        const int defaultHeight = 600;
        size.setWidth(xres <= 0 ? defaultWidth : xres);
        size.setHeight(yres <= 0 ? defaultHeight : yres);

        if (xres <= 0 || yres <= 0) {
            qWarning("EGLFS: Unable to query screen resolution, defaulting to %dx%d.\n"
                     "EGLFS: To override, set QT_QPA_EGLFS_WIDTH and QT_QPA_EGLFS_HEIGHT.",
                     defaultWidth, defaultHeight);
        }

        // override fb0 from environment var setting
        if (width)
            size.setWidth(width);
        if (height)
            size.setHeight(height);
    }

    return size;
}

QDpi QEglFSHooks::logicalDpi() const
{
    QSizeF ps = physicalScreenSize();
    QSize s = screenSize();

    return QDpi(25.4 * s.width() / ps.width(),
                25.4 * s.height() / ps.height());
}

int QEglFSHooks::screenDepth() const
{
    static int depth = qgetenv("QT_QPA_EGLFS_DEPTH").toInt();

    if (depth == 0) {
        struct fb_var_screeninfo vinfo;

        if (framebuffer != -1) {
            if (ioctl(framebuffer, FBIOGET_VSCREENINFO, &vinfo) == -1)
                qWarning("EGLFS: Could not query variable screen info.");
            else
                depth = vinfo.bits_per_pixel;
        }

        const int defaultDepth = 32;

        if (depth <= 0) {
            depth = defaultDepth;

            qWarning("EGLFS: Unable to query screen depth, defaulting to %d.\n"
                     "EGLFS: To override, set QT_QPA_EGLFS_DEPTH.", defaultDepth);
        }
    }

    return depth;
}

QImage::Format QEglFSHooks::screenFormat() const
{
    return screenDepth() == 16 ? QImage::Format_RGB16 : QImage::Format_RGB32;
}

QSurfaceFormat QEglFSHooks::surfaceFormatFor(const QSurfaceFormat &inputFormat) const
{
    return inputFormat;
}

bool QEglFSHooks::filterConfig(EGLDisplay, EGLConfig) const
{
    return true;
}

EGLNativeWindowType QEglFSHooks::createNativeWindow(const QSize &size, const QSurfaceFormat &format)
{
    Q_UNUSED(size);
    Q_UNUSED(format);
    return 0;
}

void QEglFSHooks::destroyNativeWindow(EGLNativeWindowType window)
{
    Q_UNUSED(window);
}

bool QEglFSHooks::hasCapability(QPlatformIntegration::Capability cap) const
{
    Q_UNUSED(cap);
    return false;
}

QEglFSCursor *QEglFSHooks::createCursor(QEglFSScreen *screen) const
{
    return new QEglFSCursor(screen);
}

void QEglFSHooks::waitForVSync() const
{
#if defined(FBIO_WAITFORVSYNC)
    static const bool forceSync = qgetenv("QT_QPA_EGLFS_FORCEVSYNC").toInt();
    if (forceSync && framebuffer != -1) {
        int arg = 0;
        if (ioctl(framebuffer, FBIO_WAITFORVSYNC, &arg) == -1)
            qWarning("Could not wait for vsync.");
    }
#endif
}

#ifndef EGLFS_PLATFORM_HOOKS
QEglFSHooks stubHooks;
#endif

QT_END_NAMESPACE