GdiplusFlat（4）单色画刷 和 线性渐变画刷

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在上一篇中，我们说到了通过GdipCreateFromHDC函数将HDC（设备上下文句柄）装换成GDI+的Graphics对象，并讲到了画笔的使用，这一篇就来讲讲画刷。

画刷和画笔差不多，就是画刷是画的实心的图形、

其实画刷有很多种，这里只介绍最常用的两种，分别是单色画刷和线性渐变画刷

还是和以前一样，我们必须自己声明GDI+Flat函数，自己定义GDI+Flat的数据结构。自己动手，丰衣足食。~~

对于画刷的创建和销毁，其实是GDI+调用的GDI+Flat的这几个函数：GdipCreateSolidFill、GdipCreateLineBrush和GdipDeleteBrush

我们把这两个函数自己声明出来！不用那些GDI+类的东西！只用C和Win32的最基本的数据类型！

//画刷typedef struct _PointF{float x;float y;}PointF;extern "C" int WINAPI GdipCreateSolidFill(unsigned int argb_color,int** brush);extern "C" int WINAPI GdipCreateLineBrush(PointF* point1, PointF* point2, unsigned int argb_color1,unsigned int argb_color2,int wrapMode,int** lineGradient);extern "C" int WINAPI GdipDeleteBrush(int* brush);

GdipCreateSolidFill：创建单色画刷

参数1：画刷的ARGB颜色

参数2：指向一个画刷的指针，用于接收返回的画刷，画刷是int*

GdipCreateLineBrush：创建线性渐变画刷

参数1：起点坐标，是我上面定义的PointF结构，PointF结构中：x为横坐标，y为纵坐标

参数2：终点坐标，是我上面定义的PointF结构，PointF结构中：x为横坐标，y为纵坐标

参数3：画刷的起点ARGB颜色

参数4：画刷的终点ARGB颜色

参数5：wrapMode 包围模式：WrapModeTile=0,WrapModeTileFlipX=1,WrapModeTileFlipY=2,WrapModeTileFlipXY=3,WrapModeClamp=4

其中0最为常用，为“平铺模式“。MSDN：https://msdn.microsoft.com/en-us/library/ms534407(v=vs.85).aspx

参数6：指向一个画刷的指针，用于接收返回的画刷，画刷是int*

GdipDeleteBrush：销毁画刷

参数：要销毁的画刷

以上三个函数的返回值：0成功，非0失败

通过画刷画图，以画填充矩形为例：

//画填充矩形extern "C" int WINAPI GdipFillRectangle(int graphics, int* brush, float x, float y, float width, float height);

GdipFillRectangle：画填充矩形

参数1：Graphics对象

参数2：画刷

参数3-6：矩形左上角的x坐标，y坐标，矩形宽度，矩形高度

例子：

<pre class="cpp" name="code">case WM_PAINT:HDC hdc;PAINTSTRUCT ps;hdc = BeginPaint(hwnd, &ps);int graphics;GdipCreateFromHDC(hdc, &graphics);//创建Graphics对象GdipCreateSolidFill(0x700000FF, &brush);//创建单色画刷GdipFillRectangle(graphics, brush, 10, 10, 60, 60);//用单色画刷填充矩形PointF p1; p1 = { 70, 0 };PointF p2; p2 = { 170, 0 };GdipCreateLineBrush(&p1, &p2, 0xFFFF0000, 0x400000FF, 0, &linebrush);//创建线性渐变画刷GdipFillRectangle(graphics, linebrush, 70, 70, 100, 100);//用线性渐变画刷填充矩形GdipDeleteBrush(brush);//销毁画刷GdipDeleteBrush(linebrush);//销毁画刷GdipDeleteGraphics(graphics);//销毁Graphics对象EndPaint(hwnd, &ps);return 0;//告诉系统，WM_PAINT消息我已经处理了，你那儿凉快哪儿玩去吧。

效果图：

完整源码：

#include "stdafx.h"#include <gdiplus.h>#include <gdiplusflat.h>#pragma comment(lib,"gdiplus.lib")//very important#include <windows.h>#include <windowsx.h>#pragma comment(lib,"user32.lib")#pragma comment(lib,"gdi32.lib")//GDI+Flattypedef struct _GdiplusStartupInput{unsigned int GdiplusVersion;unsigned int DebugEventCallback;BOOL SuppressBackgroundThread;BOOL SuppressExternalCodecs;}GdiplusStartupInput;extern "C" int WINAPI GdiplusStartup(int* token, GdiplusStartupInput *input, int *output);extern "C" void WINAPI GdiplusShutdown(int token);extern "C" int WINAPI GdipCreateFromHDC(HDC hdc, int* graphics);extern "C" int WINAPI GdipDeleteGraphics(int graphics);//画笔extern "C" int WINAPI GdipCreatePen1(unsigned int argb_color, float width, int unit, int** pen);extern "C" int WINAPI GdipDeletePen(int* pen);//画矩形 画直线extern "C" int WINAPI GdipDrawRectangle(int graphics, int* pen, float x, float y, float width, float height);extern "C" int WINAPI GdipDrawLine(int graphics, int* pen, float x1, float y1, float x2, float y2);//画刷typedef struct _PointF{float x;float y;}PointF;extern "C" int WINAPI GdipCreateSolidFill(unsigned int argb_color, int** brush);extern "C" int WINAPI GdipCreateLineBrush(PointF* point1, PointF* point2, unsigned int argb_color1, unsigned int argb_color2, int wrapMode, int** lineGradient);extern "C" int WINAPI GdipDeleteBrush(int* brush);//画填充矩形extern "C" int WINAPI GdipFillRectangle(int graphics, int* brush, float x, float y, float width, float height);int token;int* pen;int* brush;int* linebrush;//*************************************************************LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);WNDCLASS wc;const TCHAR* AppName = TEXT("MyWindowClass1");HWND hwnd1;int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,_In_opt_ HINSTANCE hPrevInstance,_In_ LPTSTR    lpCmdLine,_In_ int       nCmdShow){//GDI+开启GdiplusStartupInput StartupInput = { 0 };StartupInput.GdiplusVersion = 1;if (GdiplusStartup(&token, &StartupInput, NULL))MessageBox(0, TEXT("GdiPlus开启失败"), TEXT("错误"), MB_ICONERROR);//这里是在构建窗口类结构wc.style = CS_HREDRAW | CS_VREDRAW;wc.lpfnWndProc = WndProc;//窗口回调函数指针wc.cbClsExtra = 0;wc.cbWndExtra = 0;wc.hInstance = hInstance;//实例句柄wc.hIcon = LoadIcon(hInstance, TEXT("ICON_1"));wc.hCursor = LoadCursor(NULL, IDC_ARROW);//默认指针wc.hbrBackground = (HBRUSH)(COLOR_WINDOW);//默认背景颜色wc.lpszMenuName = NULL;wc.lpszClassName = AppName;//窗口类名//注册窗口类if (!RegisterClass(&wc)){MessageBox(NULL, TEXT("注册窗口类失败!"), TEXT("错误"), MB_ICONERROR);return 0;}//创建窗口int style = WS_OVERLAPPEDWINDOW;hwnd1 = CreateWindowEx(NULL, AppName, TEXT("窗口标题"), style, 50, 50, 500, 500, 0, LoadMenu(hInstance, TEXT("MENU1")), hInstance, 0);if (hwnd1 == NULL){MessageBox(NULL, TEXT("创建窗口失败!"), TEXT("错误"), MB_ICONERROR);return 0;}//无边框窗口SetWindowLong(hwnd1, GWL_STYLE, WS_OVERLAPPED | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS);//显示、更新窗口ShowWindow(hwnd1, nCmdShow);UpdateWindow(hwnd1);//消息循环MSG msg;while (GetMessage(&msg, NULL, 0, 0)){TranslateMessage(&msg);DispatchMessage(&msg);} //GDI+关闭GdiplusShutdown(token);//可以把这个写在消息循环后面，程序退出就销毁，或者在不需要GDI+时调用，比如GDI+窗口的WM_DESTROY消息里调用return msg.wParam;}LRESULT CALLBACK WndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam){switch (uMsg){case WM_PAINT:HDC hdc;PAINTSTRUCT ps;hdc = BeginPaint(hwnd, &ps);int graphics;GdipCreateFromHDC(hdc, &graphics);//创建Graphics对象GdipCreateSolidFill(0x700000FF, &brush);//创建单色画刷GdipFillRectangle(graphics, brush, 10, 10, 60, 60);//用单色画刷填充矩形PointF p1; p1 = { 70, 0 };PointF p2; p2 = { 170, 0 };GdipCreateLineBrush(&p1, &p2, 0xFFFF0000, 0x400000FF, 0, &linebrush);//创建线性渐变画刷GdipFillRectangle(graphics, linebrush, 70, 70, 100, 100);//用线性渐变画刷填充矩形if (0){//这是上一篇中画笔的代码，用if0作废GdipCreatePen1(0x60FF2015, 1, 2, &pen);//创建画笔GdipDrawRectangle(graphics, pen, 20, 20, 120, 120);//画矩形GdipDrawLine(graphics, pen, 50, 60, 170, 340);//画直线GdipDeletePen(pen);//销毁画笔}GdipDeleteBrush(brush);//销毁画刷GdipDeleteBrush(linebrush);//销毁画刷GdipDeleteGraphics(graphics);//销毁Graphics对象EndPaint(hwnd, &ps);return 0;//告诉系统，WM_PAINT消息我已经处理了，你那儿凉快哪儿玩去吧。case WM_CREATE:break;case WM_DESTROY://窗口已经销毁PostQuitMessage(0);//退出消息循环，结束应用程序return 0;break;case WM_LBUTTONDOWN://鼠标左键按下//让无边框窗口能够拖动(在窗口客户区拖动)PostMessage(hwnd, WM_SYSCOMMAND, 61458, 0);break;/*case WM_MOUSEMOVE://鼠标移动int xPos, yPos;xPos = GET_X_LPARAM(lParam);//鼠标位置X坐标yPos = GET_Y_LPARAM(lParam);//鼠标位置Y坐标//不要用LOWORD和HIWORD获取坐标，因为坐标有可能是负的break;*/default:break;}return DefWindowProc(hwnd, uMsg, wParam, lParam);//其他消息交给系统处理}