/**
 * Created by G-Canvas Open Source Team.
 * Copyright (c) 2017, Alibaba, Inc. All rights reserved.
 *
 * This source code is licensed under the Apache Licence 2.0.
 * For the full copyright and license information, please view
 * the LICENSE file in the root directory of this source tree.
 */


#include "GCanvas2dContext.h"
#include "CharacterSet.h"
#include "gcanvas/GCanvas2dContext.h"
#include "support/Log.h"

void GCanvasContext::DrawTextWithLength(const char *text, int strLength, float x, float y,
                                 bool isStroke, float maxWidth)
{
    if (strLength == 0)
    {
        strLength = static_cast<int>(strlen(text));
    }

    const GCompositeOperation old_op = mCurrentState->mGlobalCompositeOp;
    DoSetGlobalCompositeOperation(COMPOSITE_OP_SOURCE_OVER, COMPOSITE_OP_SOURCE_OVER);

    // scaleWidth
    float scaleWidth = 1.0;
    if (fabs(maxWidth - SHRT_MAX) > 1) {
        // 对maxwidth进行判断，避免默认值导致的每次measure操作
        float measureWidth = MeasureTextWidth(text);
        if (measureWidth > maxWidth)
        {
            scaleWidth = maxWidth / measureWidth;
        }
    }


    Utf8ToUCS2 *lbData = new Utf8ToUCS2(text, strLength);
    FillText(lbData->ucs2, lbData->ucs2len, x, y,
                             isStroke, scaleWidth);

    delete lbData;
    DoSetGlobalCompositeOperation(old_op, old_op);
}



void GCanvasContext::DoSetGlobalCompositeOperation(GCompositeOperation op, GCompositeOperation alphaOp)
{
    if (mCurrentState->mGlobalCompositeOp == op)
    {
        return;
    }
    SendVertexBufferToGPU();

    GBlendOperationFuncs funcs = GCompositeOperationFuncs(op);

    GBlendOperationFuncs alphaFuncs = GCompositeOperationFuncs(alphaOp);

    glBlendFuncSeparate(funcs.source, funcs.destination,
                        alphaFuncs.source, alphaFuncs.destination);

    mCurrentState->mGlobalCompositeOp = op;
}