GDI+學習及代碼總結之------畫線、區域填充、寫字

轉自：http://blog.csdn.net/harvic880925/article/details/9023329

《精通GDI編程》裏的代碼，在學習過程中對它加以總結，以防以後用到，所有代碼都是在MFC 單文檔中實現的，寫在View::OnDraw(CDC */*pDC*/)中

畫線/邊框（Pen）

1、畫單線-------DrawLine

Pen pen(Color(255,0,0,0),3);
PointF L_PTStart(0,0);
PointF L_PTEnd(100,10);
graphics.DrawLine(&pen,L_PTStart,L_PTEnd);

2、連接線--------DrawLines

Pen blackPen(Color(255, 0, 0, 0), 3);

PointF point1(10.0f, 10.0f);
PointF point2(10.0f, 100.0f);
PointF point3(200.0f, 50.0f);
PointF point4(250.0f, 80.0f);

PointF points[4] = {point1, point2, point3, point4};
PointF* pPoints = points;

graphics.DrawLines(&blackPen, pPoints, 4);

講解：points數組中的每個點都是連接線上的轉折點，DrawLines會把它們按照順序一個個連接起來

3、畫矩形-----DrawRectangle,只畫邊框，不畫背景色

Pen blackPen(Color(255,255, 0, 0), 3);
Rect rect(0, 0, 100, 100);
graphics.DrawRectangle(&blackPen, rect);

4、一次畫多個矩形----DrawRectangles

Pen blackPen(Color(255, 0, 255, 0), 3);
// 定義三個矩形
RectF rect1(0.0f, 0.0f, 50.0f, 60.0f);
RectF rect2(60.0f, 70.0f, 70.0f, 100.0f);
RectF rect3(100.0f, 0.0f, 50.0f, 50.0f);
RectF rects[] = {rect1, rect2, rect3};
//RectF是對Rect的封裝
graphics.DrawRectangles(&blackPen, rects, 3);

5、畫曲線-----DrawCurve

Pen greenPen(Color::Green, 3);
PointF point1(100.0f, 100.0f);
PointF point2(200.0f, 50.0f);
PointF point3(400.0f, 10.0f);
PointF point4(500.0f, 100.0f);

PointF curvePoints[4] = {
    point1,
    point2,
    point3,
    point4};

    PointF* pcurvePoints = curvePoints;

    // 畫曲線
    graphics.DrawCurve(&greenPen, curvePoints, 4);

    //畫連接點和直線連接線
    SolidBrush redBrush(Color::Red);
    graphics.FillEllipse(&redBrush, Rect(95, 95, 10, 10));//畫連接點
    graphics.FillEllipse(&redBrush, Rect(195, 45, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(395, 5, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(495, 95, 10, 10));

    Pen redPen(Color::Red, 2);
    graphics.DrawLines(&redPen,curvePoints,4);//畫連接線

注意：這裏爲了比較畫曲線與畫直線連接線的區別，我用綠色畫的曲線，用紅色畫的直線連接線，同時畫出了連接點，大家可以比較一下。

6、畫閉合曲線

Pen greenPen(Color::Green, 3);
PointF point1(100.0f, 100.0f);//開始點
PointF point2(200.0f, 50.0f);
PointF point3(400.0f, 10.0f);
PointF point4(500.0f, 100.0f);
PointF point5(600.0f, 200.0f);
PointF point6(700.0f, 400.0f);
PointF point7(500.0f, 500.0f);//結束點

PointF curvePoints[7] = {
    point1,
    point2,
    point3,
    point4,
    point5,
    point6,
    point7};

    PointF* pcurvePoints = curvePoints;

    //畫閉合曲線
    graphics.DrawClosedCurve(&greenPen, curvePoints, 7);

    //畫連接點
    SolidBrush redBrush(Color::Red);
    SolidBrush startBrush(Color::Blue);
    SolidBrush endBrush(Color::Black);
    graphics.FillEllipse(&startBrush, Rect(95, 95, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(495, 95, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(195, 45, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(395, 5, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(595, 195, 10, 10));
    graphics.FillEllipse(&redBrush, Rect(695, 395, 10, 10));
    graphics.FillEllipse(&endBrush, Rect(495, 495, 10, 10));

注意：藍色點是開始點，黑色點是結束點
7、畫多邊形-----DrawPolygon，既然能畫閉合的曲線，肯定也有閉合的直線，當然閉合的直線也就是所謂的多邊形

Pen blackPen(Color(255, 0, 0, 0), 3);
//創建點數組，DrawPolygon會按這些點的順序逐個連接起來
PointF point1(100.0f, 100.0f);
PointF point2(200.0f, 130.0f);
PointF point3(150.0f, 200.0f);
PointF point4(50.0f, 200.0f);
PointF point5(0.0f, 130.0f);
PointF points[5] = {point1, point2, point3, point4, point5};
PointF* pPoints = points;
// 畫多邊形，也就是閉合直線
graphics.DrawPolygon(&blackPen, pPoints, 5);

8、畫弧線----DrawArc

Pen redPen(Color::Red, 3);
RectF ellipseRect(0, 0, 200, 100);
REAL startAngle = 0.0f;//起始度數
REAL sweepAngle = 90.0f;//結尾時的度數
// 畫弧線
graphics.DrawArc(&redPen, ellipseRect, startAngle, sweepAngle);
//畫出邊框，做爲參考
Pen greenPen(Color::Green, 1);
graphics.DrawRectangle(&greenPen,ellipseRect);

9、畫扇形----DrawPie

Pen blackPen(Color(255, 0, 255, 0), 3);

// 定義橢圓，然後在裏面截一部分作爲最終的扇形
RectF ellipseRect(0, 0, 200, 100);
REAL startAngle = 40.0f;
REAL sweepAngle = 100.0f;

//畫扇形
graphics.DrawPie(&blackPen, ellipseRect, startAngle, sweepAngle);

先出效果圖：

這裏要對它兩上名詞講解一下，什麼叫startAngle(開始度數)，什麼叫sweepAngle(範圍度數也能叫掃過度數，我譯的，嘿嘿)

看下MSDN裏對DrawPie函數的講解就會懂了，裏面有這個圖，給大家看一下

填充區域（SolidBrush）

1、填充閉合區域----FillClosedCurve，邊框對應：DrawClosedCurve

SolidBrush blackBrush(Color(255, 0, 0, 0));

PointF point1(100.0f, 100.0f);
PointF point2(200.0f, 50.0f);
PointF point3(250.0f, 200.0f);
PointF point4(50.0f, 150.0f);
PointF points[4] = {point1, point2, point3, point4};

//填充閉合區域
graphics.FillClosedCurve(&blackBrush, points, 4);
//爲閉合區域畫邊框
Pen curPen(Color::Green,3);
graphics.DrawClosedCurve(&curPen,points,4);

注意：從結果圖中也可以看出填充區域（背景）和邊框是分離的，用FillClosedCurve來填充背景色，用DrawClosedCurve來畫邊框

2、填充橢圓---FillEllipse，邊框對應：DrawEllipse

SolidBrush blackBrush(Color(255, 0, 0, 0));
RectF ellipseRect(0.0f, 0.6f, 200.8f, 100.9f);
//填充橢圓
graphics.FillEllipse(&blackBrush, ellipseRect);
//畫邊框，當然也可以不畫
Pen borderPen(Color::Green,3);
graphics.DrawEllipse(&borderPen,ellipseRect);

還有類似的幾個函數，這裏就不一 一講解了

它們是：

FillPie(Brush* brush, RectF& rect, REAL startAngle, REAL sweepAngle)    //填充扇形，對應DrawPie

FillPolygon(Brush* brush, PointF* points, INT count)                       //填充多邊形，對應DrawPolygon

FillRectangle(Brush* brush, RectF& rect)                                          //填充矩形,對應DrawRectangle

FillRectangles(Brush* brush, RectF* rects, INT count)                   //同時填充多個矩形，對應DrawRectangles

還有是關於路徑和區域的，先記下，後面再說

Status FillPath( const Brush* brush, const GraphicsPath*path);

Status FillRegion( const Brush* brush, const Region*region);

寫字（SolidBrush）

形式一：Status DrawString( const WCHAR*string, INTlength, const Font* font, const PointF&origin, const Brush*brush);

Graphics graphics(this->GetDC()->m_hDC);

SolidBrush brush(Color(255,0,0,255));

FontFamily fontfamily(L"宋體");
Font font(&fontfamily,24,FontStyleRegular,UnitPixel);

PointF  pointf(0,0);//PointF類對點進行了封裝，這裏是指定寫字的開始點

graphics.DrawString(L"GDI寫字",-1,&font,pointf,&brush);
//DrawString還有另外兩個重載形式，能實現更強大的功能

形式二：Status DrawString( const WCHAR*string, INT length, const Font*font, const RectF&layoutRect, const StringFormat*stringFormat, const Brush*brush);

WCHAR string[256];
wcscpy(string, L"Sample Text");

// Initialize arguments.
Font myFont(L"Arial", 16);//字體
RectF layoutRect(0.0f, 0.0f, 200.0f, 50.0f);//矩形

//設定字體格式
StringFormat format;
format.SetAlignment(StringAlignmentCenter); //水平方向的對齊方式，這裏設置爲水平居中
format.SetLineAlignment(StringAlignmentFar);//垂直方向的對齊方式，這裏設置爲垂直居下
SolidBrush blackBrush(Color(255, 0, 0, 0));

//畫矩形邊框
graphics.DrawRectangle(&Pen(Color::Green, 3), layoutRect);
//填充矩形背景
graphics.FillRectangle(&SolidBrush(Color(255,255,0,0)),layoutRect);
//DrawString，一定要先畫背景再寫字，要不然，字會被背景覆蓋
graphics.DrawString(
    string,
    wcslen(string),
    &myFont,
    layoutRect,
    &format,
    &blackBrush);

形式三：Status DrawString( const WCHAR*string, INTlength, const Font* font, const PointF&origin, const StringFormat*stringFormat, const Brush* brush);

這種形式是形式一與形式二的結合，指定寫字開始點和字體格式，這裏就不舉例了。