C++ Builder > TCanvas > 범례 그리기

C++ Builder XE4

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#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------

static const int kNumColor = 4;

// Microsoft color
// @ http://colorhunt.co/blog/google-microsoft-brand-colors/
static const int baseColors[][3] = {
    { 0x00, 0xA1, 0xF1 }, // R, G, B
    { 0x7C, 0xBB, 0x00 }, // R, G, B
    { 0xFF, 0xBB, 0x00 }, // R, G, B
    { 0xF6, 0x53, 0x14 }, // R, G, B
};

TColor __fastcall TForm1::getTColor(int index)
{
    if (index < 0 || index >= kNumColor) {
        return RGB(0, 0, 0);
    }
    int R = baseColors[index][0];
    int G = baseColors[index][1];
    int B = baseColors[index][2];
    return RGB(R, G, B);
}

void __fastcall TForm1::clearTImage(TImage *imgPtr)
{
    imgPtr->Canvas->Brush->Color = clWhite;
    imgPtr->Canvas->FillRect(Rect(0, 0, imgPtr->Width, imgPtr->Height));
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    drawLegends();
}

void __fastcall TForm1::drawLegends(void)
{
    // 1. 消去
    clearTImage(Image1);

    // 2. 凡例の描画
    int step_y = 20; // 結果を見ながら調整した
    for(int idx=0; idx < kNumColor; idx++) {
        char code = 'A' + idx;
        writeTextOnTImage(Image1, /*x=*/30, /*y=*/10 + step_y * idx, String(code)); // 位置30は任意
        drawLegentColor(Image1, /*x=*/14, /*y=*/14 + step_y * idx, getTColor(/*index=*/idx)); // 位置14は任意
    }
}

void __fastcall TForm1::writeTextOnTImage(TImage *imgPtr, int x, int y, String text)
{
    imgPtr->Canvas->Font->Color = clBlack;
    imgPtr->Canvas->Brush->Color = clWhite; // これがないとdrawLegendColor()の後に文字に背景色が付く
    imgPtr->Canvas->Font->Size = 10; // サイズ10は任意

    imgPtr->Canvas->TextOutW(x, y, text.c_str());
}

void __fastcall TForm1::drawLegentColor(TImage *imgPtr, int x, int y, TColor acolor)
{
    imgPtr->Canvas->Brush->Color = acolor;
    imgPtr->Canvas->FillRect(Rect(x, y, x+10, y+10)); // サイズ10は任意
}
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