juce_linux_Windowing.cpp

/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE 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.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

extern Display* display;
extern XContext windowHandleXContext;
typedef void (*WindowMessageReceiveCallback) (XEvent&);
extern WindowMessageReceiveCallback dispatchWindowMessage;


//==============================================================================
struct Atoms
{
    Atoms()
    {
        Protocols                       = getIfExists ("WM_PROTOCOLS");
        ProtocolList [TAKE_FOCUS]       = getIfExists ("WM_TAKE_FOCUS");
        ProtocolList [DELETE_WINDOW]    = getIfExists ("WM_DELETE_WINDOW");
        ProtocolList [PING]             = getIfExists ("_NET_WM_PING");
        ChangeState                     = getIfExists ("WM_CHANGE_STATE");
        State                           = getIfExists ("WM_STATE");
        UserTime                        = getCreating ("_NET_WM_USER_TIME");
        ActiveWin                       = getCreating ("_NET_ACTIVE_WINDOW");
        Pid                             = getCreating ("_NET_WM_PID");
        WindowType                      = getIfExists ("_NET_WM_WINDOW_TYPE");
        WindowState                     = getIfExists ("_NET_WM_STATE");

        XdndAware                       = getCreating ("XdndAware");
        XdndEnter                       = getCreating ("XdndEnter");
        XdndLeave                       = getCreating ("XdndLeave");
        XdndPosition                    = getCreating ("XdndPosition");
        XdndStatus                      = getCreating ("XdndStatus");
        XdndDrop                        = getCreating ("XdndDrop");
        XdndFinished                    = getCreating ("XdndFinished");
        XdndSelection                   = getCreating ("XdndSelection");

        XdndTypeList                    = getCreating ("XdndTypeList");
        XdndActionList                  = getCreating ("XdndActionList");
        XdndActionCopy                  = getCreating ("XdndActionCopy");
        XdndActionPrivate               = getCreating ("XdndActionPrivate");
        XdndActionDescription           = getCreating ("XdndActionDescription");

        allowedMimeTypes[0]             = getCreating ("UTF8_STRING");
        allowedMimeTypes[1]             = getCreating ("text/plain;charset=utf-8");
        allowedMimeTypes[2]             = getCreating ("text/plain");
        allowedMimeTypes[3]             = getCreating ("text/uri-list");

        externalAllowedFileMimeTypes[0] = getCreating ("text/uri-list");
        externalAllowedTextMimeTypes[0] = getCreating ("text/plain");

        allowedActions[0]               = getCreating ("XdndActionMove");
        allowedActions[1]               = XdndActionCopy;
        allowedActions[2]               = getCreating ("XdndActionLink");
        allowedActions[3]               = getCreating ("XdndActionAsk");
        allowedActions[4]               = XdndActionPrivate;
    }

    static const Atoms& get()
    {
        static Atoms atoms;
        return atoms;
    }

    enum ProtocolItems
    {
        TAKE_FOCUS = 0,
        DELETE_WINDOW = 1,
        PING = 2
    };

    Atom Protocols, ProtocolList[3], ChangeState, State, UserTime,
         ActiveWin, Pid, WindowType, WindowState,
         XdndAware, XdndEnter, XdndLeave, XdndPosition, XdndStatus,
         XdndDrop, XdndFinished, XdndSelection, XdndTypeList, XdndActionList,
         XdndActionDescription, XdndActionCopy, XdndActionPrivate,
         allowedActions[5],
         allowedMimeTypes[4],
         externalAllowedFileMimeTypes[1],
         externalAllowedTextMimeTypes[1];

    static const unsigned long DndVersion;

    static Atom getIfExists (const char* name)    { return XInternAtom (display, name, True); }
    static Atom getCreating (const char* name)    { return XInternAtom (display, name, False); }

    static String getName (const Atom atom)
    {
        if (atom == None)
            return "None";

        return String (XGetAtomName (display, atom));
    }

    static bool isMimeTypeFile (const Atom atom)  { return getName (atom).equalsIgnoreCase ("text/uri-list"); }
};

const unsigned long Atoms::DndVersion = 3;

//==============================================================================
struct GetXProperty
{
    GetXProperty (Window window, Atom atom, long offset, long length, bool shouldDelete, Atom requestedType)
        : data (nullptr)
    {
        success = (XGetWindowProperty (display, window, atom, offset, length,
                                       (Bool) shouldDelete, requestedType, &actualType,
                                       &actualFormat, &numItems, &bytesLeft, &data) == Success)
                    && data != nullptr;
    }

    ~GetXProperty()
    {
        if (data != nullptr)
            XFree (data);
    }

    bool success;
    unsigned char* data;
    unsigned long numItems, bytesLeft;
    Atom actualType;
    int actualFormat;
};

//==============================================================================
namespace Keys
{
    enum MouseButtons
    {
        NoButton = 0,
        LeftButton = 1,
        MiddleButton = 2,
        RightButton = 3,
        WheelUp = 4,
        WheelDown = 5
    };

    static int AltMask = 0;
    static int NumLockMask = 0;
    static bool numLock = false;
    static bool capsLock = false;
    static char keyStates [32];
    static const int extendedKeyModifier = 0x10000000;
}

bool KeyPress::isKeyCurrentlyDown (const int keyCode)
{
    int keysym;

    if (keyCode & Keys::extendedKeyModifier)
    {
        keysym = 0xff00 | (keyCode & 0xff);
    }
    else
    {
        keysym = keyCode;

        if (keysym == (XK_Tab & 0xff)
            || keysym == (XK_Return & 0xff)
            || keysym == (XK_Escape & 0xff)
            || keysym == (XK_BackSpace & 0xff))
        {
            keysym |= 0xff00;
        }
    }

    ScopedXLock xlock;

    const int keycode = XKeysymToKeycode (display, keysym);

    const int keybyte = keycode >> 3;
    const int keybit = (1 << (keycode & 7));
    return (Keys::keyStates [keybyte] & keybit) != 0;
}

//==============================================================================
#if JUCE_USE_XSHM
namespace XSHMHelpers
{
    static int trappedErrorCode = 0;
    extern "C" int errorTrapHandler (Display*, XErrorEvent* err)
    {
        trappedErrorCode = err->error_code;
        return 0;
    }

    static bool isShmAvailable() noexcept
    {
        static bool isChecked = false;
        static bool isAvailable = false;

        if (! isChecked)
        {
            isChecked = true;
            int major, minor;
            Bool pixmaps;

            ScopedXLock xlock;

            if (XShmQueryVersion (display, &major, &minor, &pixmaps))
            {
                trappedErrorCode = 0;
                XErrorHandler oldHandler = XSetErrorHandler (errorTrapHandler);

                XShmSegmentInfo segmentInfo;
                zerostruct (segmentInfo);

                XImage* xImage = XShmCreateImage (display, DefaultVisual (display, DefaultScreen (display)),
                                                  24, ZPixmap, 0, &segmentInfo, 50, 50);

                if ((segmentInfo.shmid = shmget (IPC_PRIVATE,
                                                 xImage->bytes_per_line * xImage->height,
                                                 IPC_CREAT | 0777)) >= 0)
                {
                    segmentInfo.shmaddr = (char*) shmat (segmentInfo.shmid, 0, 0);

                    if (segmentInfo.shmaddr != (void*) -1)
                    {
                        segmentInfo.readOnly = False;
                        xImage->data = segmentInfo.shmaddr;
                        XSync (display, False);

                        if (XShmAttach (display, &segmentInfo) != 0)
                        {
                            XSync (display, False);
                            XShmDetach (display, &segmentInfo);

                            isAvailable = true;
                        }
                    }

                    XFlush (display);
                    XDestroyImage (xImage);

                    shmdt (segmentInfo.shmaddr);
                }

                shmctl (segmentInfo.shmid, IPC_RMID, 0);

                XSetErrorHandler (oldHandler);
                if (trappedErrorCode != 0)
                    isAvailable = false;
            }
        }

        return isAvailable;
    }
}
#endif

//==============================================================================
#if JUCE_USE_XRENDER
namespace XRender
{
    typedef Status (*tXRenderQueryVersion) (Display*, int*, int*);
    typedef XRenderPictFormat* (*tXRenderFindStandardFormat) (Display*, int);
    typedef XRenderPictFormat* (*tXRenderFindFormat) (Display*, unsigned long, XRenderPictFormat*, int);
    typedef XRenderPictFormat* (*tXRenderFindVisualFormat) (Display*, Visual*);

    static tXRenderQueryVersion xRenderQueryVersion = nullptr;
    static tXRenderFindStandardFormat xRenderFindStandardFormat = nullptr;
    static tXRenderFindFormat xRenderFindFormat = nullptr;
    static tXRenderFindVisualFormat xRenderFindVisualFormat = nullptr;

    static bool isAvailable()
    {
        static bool hasLoaded = false;

        if (! hasLoaded)
        {
            ScopedXLock xlock;
            hasLoaded = true;

            if (void* h = dlopen ("libXrender.so", RTLD_GLOBAL | RTLD_NOW))
            {
                xRenderQueryVersion         = (tXRenderQueryVersion)        dlsym (h, "XRenderQueryVersion");
                xRenderFindStandardFormat   = (tXRenderFindStandardFormat)  dlsym (h, "XRenderFindStandardFormat");
                xRenderFindFormat           = (tXRenderFindFormat)          dlsym (h, "XRenderFindFormat");
                xRenderFindVisualFormat     = (tXRenderFindVisualFormat)    dlsym (h, "XRenderFindVisualFormat");
            }

            if (xRenderQueryVersion != nullptr
                 && xRenderFindStandardFormat != nullptr
                 && xRenderFindFormat != nullptr
                 && xRenderFindVisualFormat != nullptr)
            {
                int major, minor;
                if (xRenderQueryVersion (display, &major, &minor))
                    return true;
            }

            xRenderQueryVersion = nullptr;
        }

        return xRenderQueryVersion != nullptr;
    }

    static XRenderPictFormat* findPictureFormat()
    {
        ScopedXLock xlock;
        XRenderPictFormat* pictFormat = nullptr;

        if (isAvailable())
        {
            pictFormat = xRenderFindStandardFormat (display, PictStandardARGB32);

            if (pictFormat == nullptr)
            {
                XRenderPictFormat desiredFormat;
                desiredFormat.type = PictTypeDirect;
                desiredFormat.depth = 32;

                desiredFormat.direct.alphaMask = 0xff;
                desiredFormat.direct.redMask   = 0xff;
                desiredFormat.direct.greenMask = 0xff;
                desiredFormat.direct.blueMask  = 0xff;

                desiredFormat.direct.alpha = 24;
                desiredFormat.direct.red   = 16;
                desiredFormat.direct.green = 8;
                desiredFormat.direct.blue  = 0;

                pictFormat = xRenderFindFormat (display,
                                                PictFormatType | PictFormatDepth
                                                 | PictFormatRedMask | PictFormatRed
                                                 | PictFormatGreenMask | PictFormatGreen
                                                 | PictFormatBlueMask | PictFormatBlue
                                                 | PictFormatAlphaMask | PictFormatAlpha,
                                                &desiredFormat,
                                                0);
            }
        }

        return pictFormat;
    }
}
#endif

//==============================================================================
namespace Visuals
{
    static Visual* findVisualWithDepth (const int desiredDepth) noexcept
    {
        ScopedXLock xlock;

        Visual* visual = nullptr;
        int numVisuals = 0;
        long desiredMask = VisualNoMask;
        XVisualInfo desiredVisual;

        desiredVisual.screen = DefaultScreen (display);
        desiredVisual.depth = desiredDepth;

        desiredMask = VisualScreenMask | VisualDepthMask;

        if (desiredDepth == 32)
        {
            desiredVisual.c_class    = TrueColor;
            desiredVisual.red_mask   = 0x00FF0000;
            desiredVisual.green_mask = 0x0000FF00;
            desiredVisual.blue_mask  = 0x000000FF;
            desiredVisual.bits_per_rgb = 8;

            desiredMask |= VisualClassMask;
            desiredMask |= VisualRedMaskMask;
            desiredMask |= VisualGreenMaskMask;
            desiredMask |= VisualBlueMaskMask;
            desiredMask |= VisualBitsPerRGBMask;
        }

        XVisualInfo* xvinfos = XGetVisualInfo (display,
                                               desiredMask,
                                               &desiredVisual,
                                               &numVisuals);

        if (xvinfos != nullptr)
        {
            for (int i = 0; i < numVisuals; i++)
            {
                if (xvinfos[i].depth == desiredDepth)
                {
                    visual = xvinfos[i].visual;
                    break;
                }
            }

            XFree (xvinfos);
        }

        return visual;
    }

    static Visual* findVisualFormat (const int desiredDepth, int& matchedDepth) noexcept
    {
        Visual* visual = nullptr;

        if (desiredDepth == 32)
        {
           #if JUCE_USE_XSHM
            if (XSHMHelpers::isShmAvailable())
            {
               #if JUCE_USE_XRENDER
                if (XRender::isAvailable())
                {
                    XRenderPictFormat* pictFormat = XRender::findPictureFormat();

                    if (pictFormat != 0)
                    {
                        int numVisuals = 0;
                        XVisualInfo desiredVisual;
                        desiredVisual.screen = DefaultScreen (display);
                        desiredVisual.depth = 32;
                        desiredVisual.bits_per_rgb = 8;

                        XVisualInfo* xvinfos = XGetVisualInfo (display,
                                                               VisualScreenMask | VisualDepthMask | VisualBitsPerRGBMask,
                                                               &desiredVisual, &numVisuals);
                        if (xvinfos != nullptr)
                        {
                            for (int i = 0; i < numVisuals; ++i)
                            {
                                XRenderPictFormat* pictVisualFormat = XRender::xRenderFindVisualFormat (display, xvinfos[i].visual);

                                if (pictVisualFormat != nullptr
                                     && pictVisualFormat->type == PictTypeDirect
                                     && pictVisualFormat->direct.alphaMask)
                                {
                                    visual = xvinfos[i].visual;
                                    matchedDepth = 32;
                                    break;
                                }
                            }

                            XFree (xvinfos);
                        }
                    }
                }
               #endif
                if (visual == nullptr)
                {
                    visual = findVisualWithDepth (32);
                    if (visual != nullptr)
                        matchedDepth = 32;
                }
            }
           #endif
        }

        if (visual == nullptr && desiredDepth >= 24)
        {
            visual = findVisualWithDepth (24);
            if (visual != nullptr)
                matchedDepth = 24;
        }

        if (visual == nullptr && desiredDepth >= 16)
        {
            visual = findVisualWithDepth (16);
            if (visual != nullptr)
                matchedDepth = 16;
        }

        return visual;
    }
}

//==============================================================================
class XBitmapImage  : public ImagePixelData
{
public:
    XBitmapImage (const Image::PixelFormat format, const int w, const int h,
                  const bool clearImage, const int imageDepth_, Visual* visual)
        : ImagePixelData (format, w, h),
          imageDepth (imageDepth_),
          gc (None)
    {
        jassert (format == Image::RGB || format == Image::ARGB);

        pixelStride = (format == Image::RGB) ? 3 : 4;
        lineStride = ((w * pixelStride + 3) & ~3);

        ScopedXLock xlock;

       #if JUCE_USE_XSHM
        usingXShm = false;

        if ((imageDepth > 16) && XSHMHelpers::isShmAvailable())
        {
            zerostruct (segmentInfo);

            segmentInfo.shmid = -1;
            segmentInfo.shmaddr = (char *) -1;
            segmentInfo.readOnly = False;

            xImage = XShmCreateImage (display, visual, imageDepth, ZPixmap, 0, &segmentInfo, w, h);

            if (xImage != nullptr)
            {
                if ((segmentInfo.shmid = shmget (IPC_PRIVATE,
                                                 xImage->bytes_per_line * xImage->height,
                                                 IPC_CREAT | 0777)) >= 0)
                {
                    if (segmentInfo.shmid != -1)
                    {
                        segmentInfo.shmaddr = (char*) shmat (segmentInfo.shmid, 0, 0);

                        if (segmentInfo.shmaddr != (void*) -1)
                        {
                            segmentInfo.readOnly = False;

                            xImage->data = segmentInfo.shmaddr;
                            imageData = (uint8*) segmentInfo.shmaddr;

                            if (XShmAttach (display, &segmentInfo) != 0)
                                usingXShm = true;
                            else
                                jassertfalse;
                        }
                        else
                        {
                            shmctl (segmentInfo.shmid, IPC_RMID, 0);
                        }
                    }
                }
            }
        }

        if (! usingXShm)
       #endif
        {
            imageDataAllocated.allocate (lineStride * h, format == Image::ARGB && clearImage);
            imageData = imageDataAllocated;

            xImage = (XImage*) ::calloc (1, sizeof (XImage));

            xImage->width = w;
            xImage->height = h;
            xImage->xoffset = 0;
            xImage->format = ZPixmap;
            xImage->data = (char*) imageData;
            xImage->byte_order = ImageByteOrder (display);
            xImage->bitmap_unit = BitmapUnit (display);
            xImage->bitmap_bit_order = BitmapBitOrder (display);
            xImage->bitmap_pad = 32;
            xImage->depth = pixelStride * 8;
            xImage->bytes_per_line = lineStride;
            xImage->bits_per_pixel = pixelStride * 8;
            xImage->red_mask   = 0x00FF0000;
            xImage->green_mask = 0x0000FF00;
            xImage->blue_mask  = 0x000000FF;

            if (imageDepth == 16)
            {
                const int pixelStride = 2;
                const int lineStride = ((w * pixelStride + 3) & ~3);

                imageData16Bit.malloc (lineStride * h);
                xImage->data = imageData16Bit;
                xImage->bitmap_pad = 16;
                xImage->depth = pixelStride * 8;
                xImage->bytes_per_line = lineStride;
                xImage->bits_per_pixel = pixelStride * 8;
                xImage->red_mask   = visual->red_mask;
                xImage->green_mask = visual->green_mask;
                xImage->blue_mask  = visual->blue_mask;
            }

            if (! XInitImage (xImage))
                jassertfalse;
        }
    }

    ~XBitmapImage()
    {
        ScopedXLock xlock;

        if (gc != None)
            XFreeGC (display, gc);

       #if JUCE_USE_XSHM
        if (usingXShm)
        {
            XShmDetach (display, &segmentInfo);

            XFlush (display);
            XDestroyImage (xImage);

            shmdt (segmentInfo.shmaddr);
            shmctl (segmentInfo.shmid, IPC_RMID, 0);
        }
        else
       #endif
        {
            xImage->data = nullptr;
            XDestroyImage (xImage);
        }
    }

    LowLevelGraphicsContext* createLowLevelContext()
    {
        return new LowLevelGraphicsSoftwareRenderer (Image (this));
    }

    void initialiseBitmapData (Image::BitmapData& bitmap, int x, int y, Image::BitmapData::ReadWriteMode)
    {
        bitmap.data = imageData + x * pixelStride + y * lineStride;
        bitmap.pixelFormat = pixelFormat;
        bitmap.lineStride = lineStride;
        bitmap.pixelStride = pixelStride;
    }

    ImagePixelData* clone()
    {
        jassertfalse;
        return nullptr;
    }

    ImageType* createType() const     { return new NativeImageType(); }

    void blitToWindow (Window window, int dx, int dy, int dw, int dh, int sx, int sy)
    {
        ScopedXLock xlock;

        if (gc == None)
        {
            XGCValues gcvalues;
            gcvalues.foreground = None;
            gcvalues.background = None;
            gcvalues.function = GXcopy;
            gcvalues.plane_mask = AllPlanes;
            gcvalues.clip_mask = None;
            gcvalues.graphics_exposures = False;

            gc = XCreateGC (display, window,
                            GCBackground | GCForeground | GCFunction | GCPlaneMask | GCClipMask | GCGraphicsExposures,
                            &gcvalues);
        }

        if (imageDepth == 16)
        {
            const uint32 rMask   = xImage->red_mask;
            const uint32 gMask   = xImage->green_mask;
            const uint32 bMask   = xImage->blue_mask;
            const uint32 rShiftL = jmax (0,  getShiftNeeded (rMask));
            const uint32 rShiftR = jmax (0, -getShiftNeeded (rMask));
            const uint32 gShiftL = jmax (0,  getShiftNeeded (gMask));
            const uint32 gShiftR = jmax (0, -getShiftNeeded (gMask));
            const uint32 bShiftL = jmax (0,  getShiftNeeded (bMask));
            const uint32 bShiftR = jmax (0, -getShiftNeeded (bMask));

            const Image::BitmapData srcData (Image (this), Image::BitmapData::readOnly);

            for (int y = sy; y < sy + dh; ++y)
            {
                const uint8* p = srcData.getPixelPointer (sx, y);

                for (int x = sx; x < sx + dw; ++x)
                {
                    const PixelRGB* const pixel = (const PixelRGB*) p;
                    p += srcData.pixelStride;

                    XPutPixel (xImage, x, y,
                               (((((uint32) pixel->getRed()) << rShiftL) >> rShiftR) & rMask)
                                 | (((((uint32) pixel->getGreen()) << gShiftL) >> gShiftR) & gMask)
                                 | (((((uint32) pixel->getBlue()) << bShiftL) >> bShiftR) & bMask));
                }
            }
        }

        // blit results to screen.
       #if JUCE_USE_XSHM
        if (usingXShm)
            XShmPutImage (display, (::Drawable) window, gc, xImage, sx, sy, dx, dy, dw, dh, True);
        else
       #endif
            XPutImage (display, (::Drawable) window, gc, xImage, sx, sy, dx, dy, dw, dh);
    }

private:
    //==============================================================================
    XImage* xImage;
    const int imageDepth;
    HeapBlock <uint8> imageDataAllocated;
    HeapBlock <char> imageData16Bit;
    int pixelStride, lineStride;
    uint8* imageData;
    GC gc;

   #if JUCE_USE_XSHM
    XShmSegmentInfo segmentInfo;
    bool usingXShm;
   #endif

    static int getShiftNeeded (const uint32 mask) noexcept
    {
        for (int i = 32; --i >= 0;)
            if (((mask >> i) & 1) != 0)
                return i - 7;

        jassertfalse;
        return 0;
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (XBitmapImage)
};

//==============================================================================
namespace PixmapHelpers
{
    Pixmap createColourPixmapFromImage (Display* display, const Image& image)
    {
        ScopedXLock xlock;

        const int width = image.getWidth();
        const int height = image.getHeight();
        HeapBlock <uint32> colour (width * height);
        int index = 0;

        for (int y = 0; y < height; ++y)
            for (int x = 0; x < width; ++x)
                colour[index++] = image.getPixelAt (x, y).getARGB();

        XImage* ximage = XCreateImage (display, CopyFromParent, 24, ZPixmap,
                                       0, reinterpret_cast<char*> (colour.getData()),
                                       width, height, 32, 0);

        Pixmap pixmap = XCreatePixmap (display, DefaultRootWindow (display),
                                       width, height, 24);

        GC gc = XCreateGC (display, pixmap, 0, 0);
        XPutImage (display, pixmap, gc, ximage, 0, 0, 0, 0, width, height);
        XFreeGC (display, gc);

        return pixmap;
    }

    Pixmap createMaskPixmapFromImage (Display* display, const Image& image)
    {
        ScopedXLock xlock;

        const int width = image.getWidth();
        const int height = image.getHeight();
        const int stride = (width + 7) >> 3;
        HeapBlock <char> mask;
        mask.calloc (stride * height);
        const bool msbfirst = (BitmapBitOrder (display) == MSBFirst);

        for (int y = 0; y < height; ++y)
        {
            for (int x = 0; x < width; ++x)
            {
                const char bit = (char) (1 << (msbfirst ? (7 - (x & 7)) : (x & 7)));
                const int offset = y * stride + (x >> 3);

                if (image.getPixelAt (x, y).getAlpha() >= 128)
                    mask[offset] |= bit;
            }
        }

        return XCreatePixmapFromBitmapData (display, DefaultRootWindow (display),
                                            mask.getData(), width, height, 1, 0, 1);
    }
}

static void* createDraggingHandCursor()
{
    static unsigned char dragHandData[] = { 71,73,70,56,57,97,16,0,16,0,145,2,0,0,0,0,255,255,255,0,
      0,0,0,0,0,33,249,4,1,0,0,2,0,44,0,0,0,0,16,0, 16,0,0,2,52,148,47,0,200,185,16,130,90,12,74,139,107,84,123,39,
      132,117,151,116,132,146,248,60,209,138,98,22,203,114,34,236,37,52,77,217, 247,154,191,119,110,240,193,128,193,95,163,56,60,234,98,135,2,0,59 };
    const int dragHandDataSize = 99;

    return CustomMouseCursorInfo (ImageFileFormat::loadFrom (dragHandData, dragHandDataSize), 8, 7).create();
}

//==============================================================================
class LinuxComponentPeer  : public ComponentPeer
{
public:
    LinuxComponentPeer (Component& comp, const int windowStyleFlags, Window parentToAddTo)
        : ComponentPeer (comp, windowStyleFlags),
          windowH (0), parentWindow (0),
          fullScreen (false), mapped (false),
          visual (nullptr), depth (0)
    {
        // it's dangerous to create a window on a thread other than the message thread..
        jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());

        dispatchWindowMessage = windowMessageReceive;
        repainter = new LinuxRepaintManager (this);

        createWindow (parentToAddTo);

        setTitle (component.getName());
    }

    ~LinuxComponentPeer()
    {
        // it's dangerous to delete a window on a thread other than the message thread..
        jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());

        deleteIconPixmaps();
        destroyWindow();
        windowH = 0;
    }

    // (this callback is hooked up in the messaging code)
    static void windowMessageReceive (XEvent& event)
    {
        if (event.xany.window != None)
        {
            if (LinuxComponentPeer* const peer = getPeerFor (event.xany.window))
                peer->handleWindowMessage (event);
        }
        else if (event.xany.type == KeymapNotify)
        {
            const XKeymapEvent& keymapEvent = (const XKeymapEvent&) event.xkeymap;
            memcpy (Keys::keyStates, keymapEvent.key_vector, 32);
        }
    }

    //==============================================================================
    void* getNativeHandle() const
    {
        return (void*) windowH;
    }

    static LinuxComponentPeer* getPeerFor (Window windowHandle) noexcept
    {
        XPointer peer = nullptr;

        ScopedXLock xlock;
        if (! XFindContext (display, (XID) windowHandle, windowHandleXContext, &peer))
            if (peer != nullptr && ! ComponentPeer::isValidPeer (reinterpret_cast <LinuxComponentPeer*> (peer)))
                peer = nullptr;

        return reinterpret_cast <LinuxComponentPeer*> (peer);
    }

    void setVisible (bool shouldBeVisible)
    {
        ScopedXLock xlock;
        if (shouldBeVisible)
            XMapWindow (display, windowH);
        else
            XUnmapWindow (display, windowH);
    }

    void setTitle (const String& title)
    {
        XTextProperty nameProperty;
        char* strings[] = { const_cast <char*> (title.toUTF8().getAddress()) };
        ScopedXLock xlock;

        if (XStringListToTextProperty (strings, 1, &nameProperty))
        {
            XSetWMName (display, windowH, &nameProperty);
            XSetWMIconName (display, windowH, &nameProperty);

            XFree (nameProperty.value);
        }
    }

    void setBounds (int x, int y, int w, int h, bool isNowFullScreen)
    {
        if (fullScreen && ! isNowFullScreen)
        {
            // When transitioning back from fullscreen, we might need to remove
            // the FULLSCREEN window property
            Atom fs = Atoms::getIfExists ("_NET_WM_STATE_FULLSCREEN");

            if (fs != None)
            {
                Window root = RootWindow (display, DefaultScreen (display));

                XClientMessageEvent clientMsg;
                clientMsg.display = display;
                clientMsg.window = windowH;
                clientMsg.type = ClientMessage;
                clientMsg.format = 32;
                clientMsg.message_type = Atoms::get().WindowState;
                clientMsg.data.l[0] = 0;  // Remove
                clientMsg.data.l[1] = fs;
                clientMsg.data.l[2] = 0;
                clientMsg.data.l[3] = 1;  // Normal Source

                ScopedXLock xlock;
                XSendEvent (display, root, false,
                            SubstructureRedirectMask | SubstructureNotifyMask,
                            (XEvent*) &clientMsg);
            }
        }

        fullScreen = isNowFullScreen;

        if (windowH != 0)
        {
            bounds.setBounds (x, y, jmax (1, w), jmax (1, h));

            WeakReference<Component> deletionChecker (&component);
            ScopedXLock xlock;

            XSizeHints* const hints = XAllocSizeHints();
            hints->flags  = USSize | USPosition;
            hints->x      = bounds.getX();
            hints->y      = bounds.getY();
            hints->width  = bounds.getWidth();
            hints->height = bounds.getHeight();

            if ((getStyleFlags() & (windowHasTitleBar | windowIsResizable)) == windowHasTitleBar)
            {
                hints->min_width  = hints->max_width  = hints->width;
                hints->min_height = hints->max_height = hints->height;
                hints->flags |= PMinSize | PMaxSize;
            }

            XSetWMNormalHints (display, windowH, hints);
            XFree (hints);

            XMoveResizeWindow (display, windowH,
                               bounds.getX() - windowBorder.getLeft(),
                               bounds.getY() - windowBorder.getTop(),
                               bounds.getWidth(),
                               bounds.getHeight());

            if (deletionChecker != nullptr)
            {
                updateBorderSize();
                handleMovedOrResized();
            }
        }
    }

    void setPosition (int x, int y)           { setBounds (x, y, bounds.getWidth(), bounds.getHeight(), false); }
    void setSize (int w, int h)               { setBounds (bounds.getX(), bounds.getY(), w, h, false); }
    Rectangle<int> getBounds() const          { return bounds; }
    Point<int> getScreenPosition() const      { return bounds.getPosition(); }

    Point<int> localToGlobal (const Point<int>& relativePosition)
    {
        return relativePosition + getScreenPosition();
    }

    Point<int> globalToLocal (const Point<int>& screenPosition)
    {
        return screenPosition - getScreenPosition();
    }

    void setAlpha (float /* newAlpha */)
    {
        //xxx todo!
    }

    void setMinimised (bool shouldBeMinimised)
    {
        if (shouldBeMinimised)
        {
            Window root = RootWindow (display, DefaultScreen (display));

            XClientMessageEvent clientMsg;
            clientMsg.display = display;
            clientMsg.window = windowH;
            clientMsg.type = ClientMessage;
            clientMsg.format = 32;
            clientMsg.message_type = Atoms::get().ChangeState;
            clientMsg.data.l[0] = IconicState;

            ScopedXLock xlock;
            XSendEvent (display, root, false, SubstructureRedirectMask | SubstructureNotifyMask, (XEvent*) &clientMsg);
        }
        else
        {
            setVisible (true);
        }
    }

    bool isMinimised() const
    {
        ScopedXLock xlock;
        const Atoms& atoms = Atoms::get();
        GetXProperty prop (windowH, atoms.State, 0, 64, false, atoms.State);