// TortoiseSVN - a Windows shell extension for easy version control

// Copyright (C) 2003-2007, 2013, 2016, 2021 - TortoiseSVN

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program 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.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
#include "stdafx.h"
#include "Gradient.h"

CGradient::CGradient()
{
}

CGradient::~CGradient()
{
}

void CGradient::SplitRect(const CRect& rSource, CRect& rHalf1, CRect& rHalf2, BOOL bHorz)
{
    rHalf1 = rSource;
    rHalf2 = rSource;
    if (!bHorz)
    {
        rHalf1.bottom = (rSource.bottom + rSource.top) / 2;
        rHalf2.top    = rHalf1.bottom;
    }
    else
    {
        rHalf1.right = (rSource.left + rSource.right) / 2;
        rHalf2.left  = rHalf1.right;
    }
}

void CGradient::Draw(CDC* pDC, const CRect& rect, COLORREF colorStart, COLORREF colorEnd, BOOL bHorz /* = TRUE*/, UINT nSteps /* = 64*/)
{
    for (UINT i = 0; i < nSteps; i++)
    {
        BYTE bR = static_cast<BYTE>((GetRValue(colorStart) * (nSteps - i) + GetRValue(colorEnd) * i) / nSteps);
        BYTE bG = static_cast<BYTE>((GetGValue(colorStart) * (nSteps - i) + GetGValue(colorEnd) * i) / nSteps);
        BYTE bB = static_cast<BYTE>((GetBValue(colorStart) * (nSteps - i) + GetBValue(colorEnd) * i) / nSteps);

        CBrush br(RGB(bR, bG, bB));

        CRect r2 = rect;
        if (!bHorz)
        {
            r2.top    = rect.top + ((i * rect.Height()) / nSteps);
            r2.bottom = rect.top + (((i + 1) * rect.Height()) / nSteps);
            if (r2.Height() > 0)
                pDC->FillRect(r2, &br);
        }
        else
        {
            r2.left  = rect.left + ((i * rect.Width()) / nSteps);
            r2.right = rect.left + (((i + 1) * rect.Width()) / nSteps);
            if (r2.Width() > 0)
                pDC->FillRect(r2, &br);
        }
    }
}

void CGradient::Draw(CDC* pDC, const CRect& rect, COLORREF colorStart, COLORREF colorMid, COLORREF colorEnd, BOOL bHorz /* = TRUE*/, UINT nSteps /* = 64*/)
{
    CRect rect1, rect2;
    SplitRect(rect, rect1, rect2, bHorz);

    Draw(pDC, rect1, colorStart, colorMid, bHorz, nSteps / 2);
    Draw(pDC, rect2, colorMid, colorEnd, bHorz, nSteps / 2);
}

#ifdef USE_GDI_GRADIENT

void CGradient::DrawGDI(CDC* pDC, const CRect& rect, COLORREF colorStart, COLORREF colorEnd, BOOL bHorz /* = TRUE*/)
{
    TRIVERTEX     vert[2]{};
    GRADIENT_RECT gRect;
    vert[0].x     = rect.left;
    vert[0].y     = rect.top;
    vert[0].Red   = GetRValue(colorStart) << 8;
    vert[0].Green = GetGValue(colorStart) << 8;
    vert[0].Blue  = GetBValue(colorStart) << 8;
    vert[0].Alpha = 0x0000;

    vert[1].x     = rect.right;
    vert[1].y     = rect.bottom;
    vert[1].Red   = GetRValue(colorEnd) << 8;
    vert[1].Green = GetGValue(colorEnd) << 8;
    vert[1].Blue  = GetBValue(colorEnd) << 8;
    vert[1].Alpha = 0x0000;

    gRect.UpperLeft  = 0;
    gRect.LowerRight = 1;
    if (bHorz)
        pDC->GradientFill(vert, 2, &gRect, 1, GRADIENT_FILL_RECT_H);
    else
        pDC->GradientFill(vert, 2, &gRect, 1, GRADIENT_FILL_RECT_V);
}

void CGradient::DrawGDI(CDC* pDC, const CRect& rect, COLORREF colorStart, COLORREF colorMid, COLORREF colorEnd, BOOL bHorz /* = TRUE*/)
{
    CRect rect1, rect2;
    SplitRect(rect, rect1, rect2, bHorz);

    DrawGDI(pDC, rect1, colorStart, colorMid, bHorz);
    DrawGDI(pDC, rect2, colorMid, colorEnd, bHorz);
}

#endif