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 * 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/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

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 */

#include <tools/color.hxx>

#include <vcl/BitmapColor.hxx>

#include <vcl/BitmapWriteAccess.hxx>

#include <bitmap/BlendFrameCache.hxx>

BlendFrameCache::BlendFrameCache(Size const& rSize, sal_uInt8 nAlpha, Color const& rColorTopLeft,

                                 Color const& rColorTopRight, Color const& rColorBottomRight,

                                 Color const& rColorBottomLeft)

    : m_aLastSize(rSize)

    , m_nLastAlpha(nAlpha)

    , m_aLastColorTopLeft(rColorTopLeft)

    , m_aLastColorTopRight(rColorTopRight)

    , m_aLastColorBottomRight(rColorBottomRight)

    , m_aLastColorBottomLeft(rColorBottomLeft)

{

    if (rSize.Width() <= 1 || rSize.Height() <= 1)

        return;

    Bitmap aContent(rSize, vcl::PixelFormat::N32_BPP);

    aContent.Erase(COL_TRANSPARENT);

    {

        BitmapScopedWriteAccess pContent(aContent);

        assert(pContent);

        if (!pContent)

            return;

        Scanline pScanContent = pContent->GetScanline(0);

        // x == 0, y == 0, top-left corner

        Color aCol(rColorTopLeft);

        aCol.SetAlpha(nAlpha);

        pContent->SetPixelOnData(pScanContent, 0, aCol);

        tools::Long x;

        const tools::Long nW(rSize.Width());

        // y == 0, top line left to right

        for (x = 1; x < nW - 1; x++)

        {

            Color aMix(rColorTopLeft);

            aMix.Merge(rColorTopRight, 255 - sal_uInt8((x * 255) / nW));

            aMix.SetAlpha(nAlpha);

            pContent->SetPixelOnData(pScanContent, x, aMix);

        }

        // x == nW - 1, y == 0, top-right corner

        // #i123690# Caution! When nW is 1, x == nW is possible (!)

        if (x < nW)

        {

            aCol = rColorTopRight;

            aCol.SetAlpha(nAlpha);

            pContent->SetPixelOnData(pScanContent, x, aCol);

        }

        tools::Long y;

        const tools::Long nH(rSize.Height());

        // x == 0 and nW - 1, left and right line top-down

        for (y = 1; y < nH - 1; y++)

        {

            pScanContent = pContent->GetScanline(y);

            Color aMixA(rColorTopLeft);

            aMixA.Merge(rColorBottomLeft, 255 - sal_uInt8((y * 255) / nH));

            aMixA.SetAlpha(nAlpha);

            pContent->SetPixelOnData(pScanContent, 0, aMixA);

            // #i123690# Caution! When nW is 1, x == nW is possible (!)

            if (x < nW)

            {

                Color aMixB(rColorTopRight);

                aMixB.Merge(rColorBottomRight, 255 - sal_uInt8((y * 255) / nH));

                aMixB.SetAlpha(nAlpha);

                pContent->SetPixelOnData(pScanContent, x, aMixB);

            }

        }

        // #i123690# Caution! When nH is 1, y == nH is possible (!)

        if (y < nH)

        {

            // x == 0, y == nH - 1, bottom-left corner

            aCol = rColorBottomLeft;

            aCol.SetAlpha(nAlpha);

            pContent->SetPixelOnData(pScanContent, 0, aCol);

            // y == nH - 1, bottom line left to right

            for (x = 1; x < nW - 1; x++)

            {

                Color aMix(rColorBottomLeft);

                aMix.Merge(rColorBottomRight, 255 - sal_uInt8(((x - 0) * 255) / nW));

                aMix.SetAlpha(nAlpha);

                pContent->SetPixelOnData(pScanContent, x, aMix);

            }

            // x == nW - 1, y == nH - 1, bottom-right corner

            // #i123690# Caution! When nW is 1, x == nW is possible (!)

            if (x < nW)

            {

                aCol = rColorBottomRight;

                aCol.SetAlpha(nAlpha);

                pContent->SetPixelOnData(pScanContent, x, aCol);

            }

        }

    }

    m_aLastResult = std::move(aContent);

}

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