EasyPlayerPro Windows播放器电子放大/局部放大播放功能实现

背景描述

在视频监控软件中，我们看到很多的软件都有电子放大功能, 按住鼠标左键不放，框选一个区域，再松开鼠标左键，即对选中的区域进行放大显示, 且可以重复该操作，逐步放大所需显示的区域, 有没有觉得，这个功能在视频监控软件中还是有他的用武地. 今天我们就来实现该功能；

实现流程

//设置电子放大起起始点int     SetElectronicZoomStartPoint(int channelId, float fXPercent, float fYPercent, unsigned char showBox);//设置电子放大结束点(在鼠标移动过程中可一直调用该函数)int     SetElectronicZoomEndPoint(int channelId, float fXPercent, float fYPercent);//设置是否放大显示int     SetElectronicZoom(int channelId, int zoomIn);//复位void    ResetElectronicZoom(int channelId);//直接设置显示区域,用于电子放大, 在某些场合, 需要直接进行缩放显示, 即可调用该函数实现int     SetRenderRect(int channelId, LPRECT lpSrcRect);

代码实现

int ChannelManager::ElectronicZoomProcess(MEDIA_VIDEO_CHANNEL_OBJ_T *pMediaChannel, EASY_FRAME_INFO *frameInfo){if (NULL == pMediaChannel)              return 0;if (NULL == frameInfo)                  return 0;ELECTRONIC_ZOOM_T *pElectoricZoom = pMediaChannel->pElectoricZoom;if (NULL == pElectoricZoom)             return 0;int nLeft = 0, nTop = 0, nRight = 0, nBottom = 0;if (pElectoricZoom->zoomIn >= 0x01){    RECT rcClient;    GetClientRect(pMediaChannel->mediaDisplay.hWnd, &rcClient);    float fLeftPercent =    pElectoricZoom->fStartPointX;    float fTopPercent  =    pElectoricZoom->fStartPointY;    float fRightPercent =   pElectoricZoom->fEndPointX;    float fBottomPercent  = pElectoricZoom->fEndPointY;    if (fRightPercent > fLeftPercent && fBottomPercent > fTopPercent)               //逐步放大    {        if (pElectoricZoom->fVideoWidth > 0)        {            int video_width = (int)pElectoricZoom->fVideoWidth;            int video_height= (int)pElectoricZoom->fVideoHeight;            nLeft = (int)((float)video_width / 100.0f * fLeftPercent);            nTop  = (int)((float)video_height/ 100.0f * fTopPercent);            nRight = (int)((float)video_width / 100.0f * fRightPercent);            nBottom  = (int)((float)video_height/ 100.0f * fBottomPercent);            if (nRight > nLeft && nBottom > nTop)            {                pElectoricZoom->fVideoWidth = (float)(nRight - nLeft);                pElectoricZoom->fVideoHeight = (float)(nBottom - nTop);                nLeft = pElectoricZoom->startVideoLeft + nLeft;                nTop = pElectoricZoom->startVideoTop + nTop;                nRight = pElectoricZoom->startVideoLeft + nRight;                nBottom = pElectoricZoom->startVideoTop + nBottom;                pElectoricZoom->startVideoLeft = nLeft;                pElectoricZoom->startVideoTop = nTop;                if (pElectoricZoom->zoomIndex + 1 <MAX_ZOOM_IN_TIMES)                {                    SetRect(&pElectoricZoom->zoomParam[pElectoricZoom->zoomIndex].rect, nLeft, nTop, nRight, nBottom);                    pElectoricZoom->zoomParam[pElectoricZoom->zoomIndex].fVideoWidth = pElectoricZoom->fVideoWidth;                    pElectoricZoom->zoomParam[pElectoricZoom->zoomIndex].fVideoHeight = pElectoricZoom->fVideoHeight;                    pElectoricZoom->zoomParam[pElectoricZoom->zoomIndex].startVideoLeft = pElectoricZoom->startVideoLeft;                    pElectoricZoom->zoomParam[pElectoricZoom->zoomIndex].startVideoTop = pElectoricZoom->startVideoTop;                    pElectoricZoom->zoomIndex ++;                }            }            else            {                int idx = pElectoricZoom->zoomIndex-2;                if (idx > 0)                {                    nLeft = pElectoricZoom->zoomParam[idx].rect.left;                    nTop = pElectoricZoom->zoomParam[idx].rect.top;                    nRight = pElectoricZoom->zoomParam[idx].rect.right;                    nBottom = pElectoricZoom->zoomParam[idx].rect.bottom;                    pElectoricZoom->fVideoWidth = pElectoricZoom->zoomParam[idx].fVideoWidth;                    pElectoricZoom->fVideoHeight = pElectoricZoom->zoomParam[idx].fVideoHeight;                    pElectoricZoom->startVideoLeft = pElectoricZoom->zoomParam[idx].startVideoLeft;                    pElectoricZoom->startVideoTop = pElectoricZoom->zoomParam[idx].startVideoTop;                }            }        }        else        {            int video_width = frameInfo->width;            int video_height= frameInfo->height;            nLeft = (int)((float)video_width / 100.0f * fLeftPercent);            nTop  = (int)((float)video_height/ 100.0f * fTopPercent);            nRight = (int)((float)video_width / 100.0f * fRightPercent);            nBottom  = (int)((float)video_height/ 100.0f * fBottomPercent);            pElectoricZoom->startVideoLeft = nLeft;            pElectoricZoom->startVideoTop = nTop;            pElectoricZoom->fVideoWidth = (float)(nRight - nLeft);            pElectoricZoom->fVideoHeight = (float)(nBottom - nTop);            SetRect(&pElectoricZoom->zoomParam[0].rect, nLeft, nTop, nRight, nBottom);            pElectoricZoom->zoomParam[0].fVideoWidth = pElectoricZoom->fVideoWidth;            pElectoricZoom->zoomParam[0].fVideoHeight = pElectoricZoom->fVideoHeight;            pElectoricZoom->zoomParam[0].startVideoLeft = pElectoricZoom->startVideoLeft;            pElectoricZoom->zoomParam[0].startVideoTop = pElectoricZoom->startVideoTop;            pElectoricZoom->zoomIndex ++;        }    }    else    {        if (pElectoricZoom->zoomIndex > 1)        {            int idx = pElectoricZoom->zoomIndex-2;            nLeft = pElectoricZoom->zoomParam[idx].rect.left;            nTop = pElectoricZoom->zoomParam[idx].rect.top;            nRight = pElectoricZoom->zoomParam[idx].rect.right;            nBottom = pElectoricZoom->zoomParam[idx].rect.bottom;            pElectoricZoom->fVideoWidth = pElectoricZoom->zoomParam[idx].fVideoWidth;            pElectoricZoom->fVideoHeight = pElectoricZoom->zoomParam[idx].fVideoHeight;            pElectoricZoom->startVideoLeft = pElectoricZoom->zoomParam[idx].startVideoLeft;            pElectoricZoom->startVideoTop = pElectoricZoom->zoomParam[idx].startVideoTop;            pElectoricZoom->zoomIndex --;        }        else        {            pElectoricZoom->fVideoWidth = 0.0f;            nLeft = 0;            nTop = 0;            nRight = frameInfo->width;            nBottom = frameInfo->height;            pElectoricZoom->zoomIndex = 0;        }    }    RECT rcSrc;    SetRect(&rcSrc, nLeft, nTop, nRight, nBottom);    CopyRect(&pMediaChannel->mediaDisplay.rcSrcRender, &rcSrc);    pElectoricZoom->zoomIn --;}return 0;}

关于EasyPlayerPro

EasyPlayerPro是一款全功能的流媒体播放器，支持RTSP、RTMP、HTTP、HLS、UDP、RTP、File等多种流媒体协议播放、支持本地文件播放，支持本地抓拍、本地录像、播放旋转、多屏播放、倍数播放等多种功能特性，核心基于ffmpeg，稳定、高效、可靠、可控，支持Windows、Android、iOS三个平台，目前在多家教育、安防、行业型公司，都得到的应用，广受好评！

EasyPlayerPro：https://github.com/EasyDSS/EasyPlayerPro

点击链接加入群【EasyPlayer & EasyPlayerPro】：544917793

技术支持

• 邮件：[e-mail]

• Tel：[phone]

• QQ交流群：544917793

EasyPlayerPro是一款非常稳定的全协议/全功能播放器组件，各平台版本需要经过授权才能商业使用，商业授权方案可以通过以上渠道进行更深入的技术与合作咨询；

获取更多信息

EasyDarwin开源流媒体服务器：www.EasyDarwin.org

EasyDSS商用流媒体解决方案：www.EasyDSS.com

EasyNVR无插件直播方案：www.EasyNVR.com

Copyright © EasyDarwin Team 2012-2017