上一次我们实现了把我们要的图片添加到CTreeCtrl控件里去，并显示图片的缩略图，现在开始我们要讲比较重要的部分--绘图区。为了实现能编辑图片的功能，绘图区应该具有如下功能。

1.  添加删除图片。

2.  放大缩小绘图区。

3.  选中一张图片，移动一张图片。

4.  绘制图片

5.  给图片添加点击事件

为了更好的实现这些功能，我模仿了cocos2d的内存管理机制以及节点结构，写了一个静态库VALib，它使用GID+渲染图片，以及实现观察者模式来监听鼠标事件。源码可一从这里下载。当然，你也可以使用cocos2d 来实现绘图区的功能。这里我使用我自己写的VALib 库来实现。

下面开始上码。

首先我们需要先继承VALib库里的VASprite类，来写一个符合我们自己需求的Image类

.h文件

#pragma once
#pragma comment(lib, "../debug/valib.lib")
#include "valib.h"
#include "SelectHandler.h"
#include "RectPlacement.h"US_VA_NS
class VaImage :public VASprite , public SelectHandler ,public CRectPlacement::TRect
{
private:bool m_TouchFlag;bool m_selectFlag;VAPoint* m_lastPoing;void init();
public:VaImage(const char* m_name);~VaImage(void);/************************************************************************//* 使用一个图片创建一个VASprite/* fileName: 图片路径/************************************************************************/static VaImage* FromFile(const WCHAR* filename);bool intersectPoint(VAPoint* pt);/************************************************************************//* 重写registerTouchDispatcher函数，使图片吞并touch事件，图片下方的图片不响应touch事件                                                                     *//************************************************************************/virtual void registerTouchDispatcher();virtual bool vaTouchBegan(VATouch* m_pTouch, VAEvent* m_pEvent);virtual void vaTouchMoved(VATouch* m_pTouch, VAEvent* m_pEvent);virtual void vaTouchEnded(VATouch* m_pTouch, VAEvent* m_pEvent);virtual void vaTouchCancelled(VATouch* m_pTouch, VAEvent* m_pEvent);virtual bool select(CPoint* pt);virtual void unselect();virtual void draw();
};

.cpp文件

#include "StdAfx.h"
#include "VaImage.h"
#include <regex>US_VA_NSVaImage::VaImage(const char* m_name):VASprite(m_name)
, m_TouchFlag(false)
, m_selectFlag(false)
, m_lastPoing(NULL)
{init();
}VaImage::~VaImage(void)
{
}VaImage* VaImage::FromFile( const WCHAR* filename )
{Bitmap* bitmap = Bitmap::FromFile( filename );//截取文件名CString tempName = filename;int m_index = tempName.Find(L"\\");while ( m_index!=-1 ){tempName = tempName.Right(tempName.GetLength()-(m_index+1));m_index = tempName.Find(L"\\");}USES_CONVERSION;const char *name = W2A(tempName.GetBuffer(tempName.GetLength()));//LPSTR)(LPCTSTR)tempName;//新建VAImage并贴上图片VaImage* vaImage = new VaImage(name);vaImage->setBitmap(bitmap);return vaImage;
}void VaImage::init()
{registryDispatch();
}bool VaImage::intersectPoint( VAPoint* pt )
{VARect rect  = getRect();VAPoint m_pt = VAPoint(pt->x, pt->y);return rect.containsPoint(m_pt);
}void VaImage::registerTouchDispatcher()
{registerWithTouchDispatcher(NULL, true);
}bool VaImage::vaTouchBegan( VATouch* m_pTouch, VAEvent* m_pEvent )
{VAPoint* pt = new VAPoint(*(m_pTouch->getLocation()));if(intersectPoint(pt)){m_TouchFlag = true;if(m_lastPoing != NULL){//setPosition(new VAPoint( getPosition()->x + (pt->x - m_lastPoing->x), getPosition()->y + (pt->y - m_lastPoing->y) ));}m_lastPoing = pt;pt->release();return true;}pt->release();return false;
}void VaImage::vaTouchMoved( VATouch* m_pTouch, VAEvent* m_pEvent )
{if(m_TouchFlag){VAPoint* pt = new VAPoint(*(m_pTouch->getLocation()));VAPoint tempPT = VAPoint( getPosition().x + (pt->x - m_lastPoing->x), getPosition().y + (pt->y - m_lastPoing->y) );setPosition(tempPT);m_lastPoing = pt;tempPT.release();pt->release();}
}void VaImage::vaTouchEnded( VATouch* m_pTouch, VAEvent* m_pEvent )
{m_TouchFlag = false;
}void VaImage::vaTouchCancelled( VATouch* m_pTouch, VAEvent* m_pEvent )
{}bool VaImage::select( CPoint* pt )
{VAPoint m_pt = VAPoint(pt->x, pt->y);if(intersectPoint(&m_pt)){m_selectFlag = true;m_pt.release();return true;}m_pt.release();unselect();return false;
}void VaImage::unselect()
{m_selectFlag = false;
}void VaImage::draw()
{VASprite::draw();//绘制边框if(m_selectFlag){VADirector* director = VADirector::sharedDirector();vertex vertex = cloneVertex();int minX = min(min(min(vertex.leftTop.X, vertex.rightTop.X), vertex.rightBottom.X), vertex.leftBottmo.X);int minY = min(min(min(vertex.leftTop.Y, vertex.rightTop.Y), vertex.rightBottom.Y), vertex.leftBottmo.Y);int maxX = max(max(max(vertex.leftTop.X, vertex.rightTop.X), vertex.rightBottom.X), vertex.leftBottmo.X);int maxY = max(max(max(vertex.leftTop.Y, vertex.rightTop.Y), vertex.rightBottom.Y), vertex.leftBottmo.Y);VARect rect  = getRect();Gdiplus::Rect r(rect.getMinX(), rect.getMinY(), rect.getMaxX()-rect.getMinX(), rect.getMaxY()-rect.getMinY());director->DrawBorder(&r);}
}

完后我们需要继承CWnd来创建一个自定义组件ImageView

.h文件

#pragma once
#include "valib.h"
#pragma comment(lib, "../debug/valib.lib")
#include "stdafx.h"
#include "ImgsTool.h"
#include "VaImage.h"// ImageView
US_VA_NS//使用valib命名空间typedef std::vector<VaImage*> VaImageArray;
class ImageView : public CWnd
{DECLARE_DYNAMIC(ImageView)
private:VADirector* m_vaDirector;VATouchDispatcher* m_vaTouchDispatcher;SelectDispatcher* m_pSelectDispatcher;Bitmap* m_canva;Bitmap* m_bgImg;float m_scale;VaImageArray imgList;float m_tagArrange;bool m_drawTage;
public:VAScene* m_scene;ImageView();virtual ~ImageView();void saveImg(CString filePath, CString type, Bitmap* bitmap = NULL);void savePlis(CString filePath, CString ImageType);void addImage(const WCHAR* filename);void setAutoArrange(float isArrange);void autoArrange();
protected:DECLARE_MESSAGE_MAP()virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam);void init();void drawBackground();void update();void draw(CDC* pDC);int GetEncoderClsid(const WCHAR* format, CLSID *pClsid);
};

.cpp 文件

// ImageView.cpp : implementation file
//
#include "stdafx.h"
#include "ImgsTool.h"
#include "ImageView.h"
#include <algorithm>
#include "PublishPlist.h"// ImageView
US_VA_NS//使用valib命名空间
IMPLEMENT_DYNAMIC(ImageView, CWnd)
enum{viewInterval,
};
ImageView::ImageView()
{}ImageView::~ImageView()
{
}BEGIN_MESSAGE_MAP(ImageView, CWnd)
END_MESSAGE_MAP()
// ImageView message handlersLRESULT ImageView::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{// TODO: Add your specialized code here and/or call the base classVATouch* pTouch = new VATouch();CPoint pt = (CPoint)lParam;pTouch->setTouchInfo((float)pt.x, (float)pt.y);switch (message){case WM_CREATE:init();break;case WM_PAINT:if(m_drawTage){update();}break;case WM_TIMER:Invalidate(FALSE);break;case WM_LBUTTONDOWN:m_pSelectDispatcher->callAllHandler(&pt);m_vaTouchDispatcher->touchesBegan(pTouch, NULL);break;case WM_MOUSEMOVE:m_vaTouchDispatcher->touchesMoved(pTouch, NULL);break;case WM_LBUTTONUP:m_vaTouchDispatcher->touchesEnded(pTouch, NULL);break;
//  case WM_COMMAND://接收控件发送来的消息的
//      break;}return CWnd::WindowProc(message, wParam, lParam);
}void ImageView::init()
{m_tagArrange = true;CRect rect;this->GetClientRect(rect);m_bgImg = new Bitmap(rect.Width(), rect.Height());drawBackground();//绘制背景m_canva = new Bitmap(rect.Width(), rect. Height());//创建画布m_pSelectDispatcher = ToolsCenter::getInstance()->getSelectDispatcher();m_vaDirector = VADirector::sharedDirector();m_vaDirector->init(this->m_hWnd);m_vaTouchDispatcher = m_vaDirector->getTouchDispatcher();m_scene = new VAScene();SetTimer(viewInterval, 5, NULL);Invalidate(FALSE);
}void ImageView::drawBackground()
{CRect rect;this->GetClientRect(rect);int size = 20;Graphics* bgG = Graphics::FromImage(m_bgImg);Bitmap* m_bgtexture = new Bitmap(size,size);Graphics* txG = Graphics::FromImage(m_bgtexture);txG->FillRectangle(&SolidBrush(Color(255,255,255)), 0, 0, size, size);txG->FillRectangle(&SolidBrush(Color(192,192,192)), size/2, 0, size/2 , size/2);txG->FillRectangle(&SolidBrush(Color(192,192,192)), 0, size/2, size/2 , size/2);bgG->FillRectangle(&TextureBrush(m_bgtexture), rect.left, rect.top, rect.right, rect.bottom);//saveImg(m_bgImg);
}
//更新窗口
void ImageView::update()
{CDC* dc = this->GetDC();draw(dc);
}
//绘制窗口
void ImageView::draw(CDC* pDC)
{CDC MemDC;             //首先定义一个显示设备对象CBitmap MemBitmap;    //定义一个位图对象CRect rect;this->GetClientRect(rect);MemDC.CreateCompatibleDC(NULL);//随后建立与屏幕显示兼容的内存显示设备MemBitmap.CreateCompatibleBitmap(pDC, rect.Width(), rect.Height()); //建立一个与屏幕显示兼容的位图，至于位图的大小嘛，可以用窗口的大小//将位图选入到内存显示设备中//只有选入了位图的内存显示设备才有地方绘图，画到指定的位图上CBitmap *pOldBit=MemDC.SelectObject(&MemBitmap);Graphics* memG = Graphics::FromHDC(MemDC);Rect destinationRect(0, 0, rect.Width(), rect.Height());memG->DrawImage(m_bgImg, destinationRect, 0, 0, rect.Width(), rect.Height(), Gdiplus::UnitPixel);m_canva = new Bitmap(rect.Width(), rect.Height());Graphics* canvaG = Graphics::FromImage(m_canva);//m_scene->update();VADirector::sharedDirector()->initDraw(memG);m_scene->draw();//绘制valib的场景里的各个图片memG->DrawImage(m_canva, destinationRect, 0, 0, rect.Width(), rect.Height(), Gdiplus::UnitPixel);delete canvaG;delete m_canva;//绘图后将内存中的图拷贝到屏幕上进行显示pDC->BitBlt(0,0, rect.Width(), rect.Height(), &MemDC,0, 0,SRCCOPY);//绘图完成后清理临时对象MemBitmap.DeleteObject();delete memG;MemDC.DeleteDC();ReleaseDC(pDC);
}void ImageView::saveImg(CString filePath, CString type,  Bitmap* bitmap /*= NULL*/)
{//m_drawTage = false;CRect rect;this->GetClientRect(rect);Gdiplus::Bitmap* _canva = new Bitmap(rect.Width(), rect.Height());Gdiplus::Graphics* canvaG = Gdiplus::Graphics::FromImage(_canva);Rect destinationRect(10, 0, rect.Width(), rect.Height());   VADirector::sharedDirector()->initDraw(canvaG);m_scene->draw();Bitmap* _bitmap;if(!bitmap)_bitmap = _canva;else_bitmap = bitmap;CLSID encoderClsid;this->GetParent();CString t = type.Right(type.GetLength()-1);if(t == "jpg") t = "jpeg";GetEncoderClsid(L"image/" + t, &encoderClsid);_bitmap->Save(filePath+type, &encoderClsid, NULL);
}void ImageView::addImage(const WCHAR* filename){VaImage* img = VaImage::FromFile(filename);m_scene->addChild(img);imgList.push_back(img);if(m_tagArrange){autoArrange();}
}void ImageView::savePlis( CString filePath, CString ImageType)
{filePath += ".plist";const wchar_t* ffd = filePath.GetBuffer(filePath.GetLength());USES_CONVERSION;const char* file = W2A(ffd);const char* _type = W2A(ImageType.GetBuffer(ImageType.GetLength()));PublishPlist* plist = new PublishPlist(file,_type, "100, 100");for(int i = 0; i< (int)imgList.size(); i++){VaImage* img = imgList.at(i);plist->addItem( img->getName(), int(img->getPosition().x), int(img->getPosition().y), int(img->getSize().width), int(img->getSize().height) );}plist->publish();
}void ImageView::setAutoArrange( float isArrange )
{m_tagArrange = isArrange;
}void ImageView::autoArrange(){//排序，由大小std::sort(imgList.begin(), imgList.end(), CRectPlacement::TRect::Greaters);CRectPlacement crp = CRectPlacement(imgList.front()->getSize().width, imgList.front()->getSize().height);for(int i = 0; i< (int)imgList.size(); i++){CRectPlacement::TRect r(0, 0, imgList.at(i)->getSize().width, imgList.at(i)->getSize().height);bool bPlaced = false;bPlaced = crp.AddAtEmptySpotAutoGrow(&r, 100000, 100000);imgList.at(i)->setPosition(VAPoint(r.x, r.y));}
}/*获取Image编码
* format: image/png, image/jpeg, image/gif
* pClsid: CLSID
*/
int ImageView::GetEncoderClsid( const WCHAR* format, CLSID *pClsid )
{UINT num = 0; //number of image encoder;UINT size = 0;   //size of the image encoder array in bytes;ImageCodecInfo *pImageCodecInfo = NULL;GetImageEncodersSize(&num, &size);if(size ==0)return -1;   //FailurepImageCodecInfo = (ImageCodecInfo *)(malloc(size));if(pImageCodecInfo==NULL)return -1;GetImageEncoders(num, size, pImageCodecInfo);for(UINT j=0; j< num; ++j){if(wcscmp(pImageCodecInfo[j].MimeType, format)==0){*pClsid = pImageCodecInfo[j].Clsid;free(pImageCodecInfo);return j;}}free(pImageCodecInfo);return -1;
}

这样我们就可以正常显示我们的图片了！

工具的完整代码可以从这里下载