/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "WindowSurfaceX11Image.h"

#include "mozilla/gfx/2D.h"

#include "mozilla/gfx/Tools.h"

#include "mozilla/gfx/gfxVars.h"

#include "gfxPlatform.h"

#include "gfx2DGlue.h"

#include <X11/extensions/shape.h>

namespace mozilla {

namespace widget {

// gfxImageSurface pixel format configuration.

#define SHAPED_IMAGE_SURFACE_BPP            4

#ifdef IS_BIG_ENDIAN

  #define SHAPED_IMAGE_SURFACE_ALPHA_INDEX  0

#else

  #define SHAPED_IMAGE_SURFACE_ALPHA_INDEX  3

#endif

WindowSurfaceX11Image::WindowSurfaceX11Image(Display* aDisplay,

                                             Window aWindow,

                                             Visual* aVisual,

                                             unsigned int aDepth,

                                             bool aIsShaped)

  : WindowSurfaceX11(aDisplay, aWindow, aVisual, aDepth)

  , mTransparencyBitmap(nullptr)

  , mTransparencyBitmapWidth(0)

  , mTransparencyBitmapHeight(0)

  , mIsShaped(aIsShaped)

{

}

WindowSurfaceX11Image::~WindowSurfaceX11Image()

{

  if (mTransparencyBitmap) {

    delete[] mTransparencyBitmap;

    Display* xDisplay = mWindowSurface->XDisplay();

    Window xDrawable = mWindowSurface->XDrawable();

    XShapeCombineMask(xDisplay, xDrawable, ShapeBounding, 0, 0, X11None, ShapeSet);

  }

}

already_AddRefed<gfx::DrawTarget>

WindowSurfaceX11Image::Lock(const LayoutDeviceIntRegion& aRegion)

{

  gfx::IntRect bounds = aRegion.GetBounds().ToUnknownRect();

  gfx::IntSize size(bounds.XMost(), bounds.YMost());

  if (!mWindowSurface || mWindowSurface->CairoStatus() ||

      !(size <= mWindowSurface->GetSize())) {

    mWindowSurface = new gfxXlibSurface(mDisplay, mWindow, mVisual, size);

  }

  if (mWindowSurface->CairoStatus()) {

    return nullptr;

  }

  if (!mImageSurface || mImageSurface->CairoStatus() ||

      !(size <= mImageSurface->GetSize())) {

    gfxImageFormat format = SurfaceFormatToImageFormat(mFormat);

    if (format == gfx::SurfaceFormat::UNKNOWN) {

      format = mDepth == 32 ?

                 gfx::SurfaceFormat::A8R8G8B8_UINT32 :

                 gfx::SurfaceFormat::X8R8G8B8_UINT32;

    }

    // Use alpha image format for shaped window as we derive

    // the shape bitmap from alpha channel. Must match SHAPED_IMAGE_SURFACE_BPP

    // and SHAPED_IMAGE_SURFACE_ALPHA_INDEX.

    if (mIsShaped) {

      format = gfx::SurfaceFormat::A8R8G8B8_UINT32;

    }

    mImageSurface = new gfxImageSurface(size, format);

    if (mImageSurface->CairoStatus()) {

      return nullptr;

    }

  }

  gfxImageFormat format = mImageSurface->Format();

  // Cairo prefers compositing to BGRX instead of BGRA where possible.

  // Cairo/pixman lacks some fast paths for compositing BGRX onto BGRA, so

  // just report it as BGRX directly in that case.

  // Otherwise, for Skia, report it as BGRA to the compositor. The alpha

  // channel will be discarded when we put the image.

  if (format == gfx::SurfaceFormat::X8R8G8B8_UINT32) {

    gfx::BackendType backend = gfxVars::ContentBackend();

    if (!gfx::Factory::DoesBackendSupportDataDrawtarget(backend)) {

#ifdef USE_SKIA

      backend = gfx::BackendType::SKIA;

#else

      backend = gfx::BackendType::CAIRO;

#endif

    }

    if (backend != gfx::BackendType::CAIRO) {

      format = gfx::SurfaceFormat::A8R8G8B8_UINT32;

    }

  }

  return gfxPlatform::CreateDrawTargetForData(mImageSurface->Data(),

                                              mImageSurface->GetSize(),

                                              mImageSurface->Stride(),

                                              ImageFormatToSurfaceFormat(format));

}

// The transparency bitmap routines are derived form the ones at nsWindow.cpp.

// The difference here is that we compose to RGBA image and then create

// the shape mask from final image alpha channel.

static inline int32_t

GetBitmapStride(int32_t width)

{

  return (width+7)/8;

}

static bool

ChangedMaskBits(gchar* aMaskBits, int32_t aMaskWidth, int32_t aMaskHeight,

                const nsIntRect& aRect, uint8_t* aImageData)

{

  int32_t stride = aMaskWidth*SHAPED_IMAGE_SURFACE_BPP;

  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();

  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);

  for (y = aRect.y; y < yMax; y++) {

      gchar* maskBytes = aMaskBits + y*maskBytesPerRow;

      uint8_t* alphas = aImageData;

      for (x = aRect.x; x < xMax; x++) {

          bool newBit = *(alphas+SHAPED_IMAGE_SURFACE_ALPHA_INDEX) > 0x7f;

          alphas += SHAPED_IMAGE_SURFACE_BPP;

          gchar maskByte = maskBytes[x >> 3];

          bool maskBit = (maskByte & (1 << (x & 7))) != 0;

          if (maskBit != newBit) {

              return true;

          }

      }

      aImageData += stride;

  }

  return false;

}

static void

UpdateMaskBits(gchar* aMaskBits, int32_t aMaskWidth, int32_t aMaskHeight,

               const nsIntRect& aRect, uint8_t* aImageData)

{

  int32_t stride = aMaskWidth*SHAPED_IMAGE_SURFACE_BPP;

  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();

  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);

  for (y = aRect.y; y < yMax; y++) {

      gchar* maskBytes = aMaskBits + y*maskBytesPerRow;

      uint8_t* alphas = aImageData;

      for (x = aRect.x; x < xMax; x++) {

          bool newBit = *(alphas+SHAPED_IMAGE_SURFACE_ALPHA_INDEX) > 0x7f;

          alphas += SHAPED_IMAGE_SURFACE_BPP;

          gchar mask = 1 << (x & 7);

          gchar maskByte = maskBytes[x >> 3];

          // Note: '-newBit' turns 0 into 00...00 and 1 into 11...11

          maskBytes[x >> 3] = (maskByte & ~mask) | (-newBit & mask);

      }

      aImageData += stride;

  }

}

void

WindowSurfaceX11Image::ResizeTransparencyBitmap(int aWidth, int aHeight)

{

  int32_t actualSize =

    GetBitmapStride(mTransparencyBitmapWidth)*mTransparencyBitmapHeight;

  int32_t newSize = GetBitmapStride(aWidth)*aHeight;

  if (actualSize < newSize) {

    delete[] mTransparencyBitmap;

    mTransparencyBitmap = new gchar[newSize];

  }

  mTransparencyBitmapWidth = aWidth;

  mTransparencyBitmapHeight = aHeight;

}

void

WindowSurfaceX11Image::ApplyTransparencyBitmap()

{

  gfx::IntSize size = mWindowSurface->GetSize();

  bool maskChanged = true;

  if (!mTransparencyBitmap) {

    mTransparencyBitmapWidth = size.width;

    mTransparencyBitmapHeight = size.height;

    int32_t byteSize =

        GetBitmapStride(mTransparencyBitmapWidth)*mTransparencyBitmapHeight;

    mTransparencyBitmap = new gchar[byteSize];

  } else {

    bool sizeChanged = (size.width != mTransparencyBitmapWidth ||

                        size.height != mTransparencyBitmapHeight);

    if (sizeChanged) {

      ResizeTransparencyBitmap(size.width, size.height);

    } else {

      maskChanged = ChangedMaskBits(mTransparencyBitmap,

        mTransparencyBitmapWidth, mTransparencyBitmapHeight,

        nsIntRect(0, 0, size.width, size.height),

        (uint8_t*)mImageSurface->Data());

    }

  }

  if (maskChanged) {

    UpdateMaskBits(mTransparencyBitmap,

                   mTransparencyBitmapWidth,

                   mTransparencyBitmapHeight,

                   nsIntRect(0, 0, size.width, size.height),

                   (uint8_t*)mImageSurface->Data());

    // We use X11 calls where possible, because GDK handles expose events

    // for shaped windows in a way that's incompatible with us (Bug 635903).

    // It doesn't occur when the shapes are set through X.

    Display* xDisplay = mWindowSurface->XDisplay();

    Window xDrawable = mWindowSurface->XDrawable();

    Pixmap maskPixmap = XCreateBitmapFromData(xDisplay,

                                              xDrawable,

                                              mTransparencyBitmap,

                                              mTransparencyBitmapWidth,

                                              mTransparencyBitmapHeight);

    XShapeCombineMask(xDisplay, xDrawable,

                      ShapeBounding, 0, 0,

                      maskPixmap, ShapeSet);

    XFreePixmap(xDisplay, maskPixmap);

  }

}

void

WindowSurfaceX11Image::Commit(const LayoutDeviceIntRegion& aInvalidRegion)

{

  RefPtr<gfx::DrawTarget> dt =

    gfx::Factory::CreateDrawTargetForCairoSurface(mWindowSurface->CairoSurface(),

                                                  mWindowSurface->GetSize());

  RefPtr<gfx::SourceSurface> surf =

    gfx::Factory::CreateSourceSurfaceForCairoSurface(mImageSurface->CairoSurface(),

                                                     mImageSurface->GetSize(),

                                                     mImageSurface->Format());

  if (!dt || !surf) {

    return;

  }

  gfx::IntRect bounds = aInvalidRegion.GetBounds().ToUnknownRect();

  gfx::Rect rect(bounds);

  if (rect.IsEmpty()) {

    return;

  }

  uint32_t numRects = aInvalidRegion.GetNumRects();

  if (numRects != 1) {

    AutoTArray<IntRect, 32> rects;

    rects.SetCapacity(numRects);

    for (auto iter = aInvalidRegion.RectIter(); !iter.Done(); iter.Next()) {

      rects.AppendElement(iter.Get().ToUnknownRect());

    }

    dt->PushDeviceSpaceClipRects(rects.Elements(), rects.Length());

  }

  if (mIsShaped) {

    ApplyTransparencyBitmap();

  }

  dt->DrawSurface(surf, rect, rect);

  if (numRects != 1) {

    dt->PopClip();

  }

}

}  // namespace widget

}  // namespace mozilla