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OpenCV實現影象上新增漢字

OpenCV已經更新至3.0了,但自帶函式putText依然不支援影象上新增漢字,所以下面實現了影象中新增漢字功能,話不多說,程式碼奉上。

void GetStringSize(HDC hDC, const char* str, int* w, int* h)
{
	SIZE size;
	GetTextExtentPoint32A(hDC, str, strlen(str), &size);
	if(w != 0) *w = size.cx;
	if(h != 0) *h = size.cy;
}
 
void paDrawString(Mat& dst, const
char* str, Point org, Scalar color, int fontSize, bool italic, bool underline) { CV_Assert(dst.data != 0 && (dst.channels() == 1 || dst.channels() == 3)); int x, y, r, b; if(org.x > dst.cols || org.y > dst.rows) return; x = org.x < 0 ? -org.x : 0; y = org.y < 0 ? -org.y : 0; LOGFONTA lf;
lf.lfHeight = - fontSize ; lf.lfWidth = 0 ; lf.lfEscapement = 0 ; lf.lfOrientation = 0 ; lf.lfWeight = 5; lf.lfItalic = italic ; //斜體 lf.lfUnderline = underline ; //下劃線 lf.lfStrikeOut = 0 ; lf.lfCharSet = DEFAULT_CHARSET ; lf.lfOutPrecision =
0 ; lf.lfClipPrecision = 0 ; lf.lfQuality = PROOF_QUALITY ; lf.lfPitchAndFamily = 0 ; strcpy (lf.lfFaceName, "華文行楷" ); HFONT hf = CreateFontIndirectA(&lf); HDC hDC = CreateCompatibleDC(0); HFONT hOldFont = (HFONT)SelectObject(hDC, hf); int strBaseW = 0, strBaseH = 0; int singleRow = 0; char buf[1 << 12]; strcpy(buf, str); //處理多行 { int nnh = 0; int cw, ch; const char* ln = strtok(buf, "\n"); while(ln != 0) { GetStringSize(hDC, ln, &cw, &ch); strBaseW = max(strBaseW, cw); strBaseH = max(strBaseH, ch); ln = strtok(0, "\n"); nnh++; } singleRow = strBaseH; strBaseH *= nnh; } if(org.x + strBaseW < 0 || org.y + strBaseH < 0) { SelectObject(hDC, hOldFont); DeleteObject(hf); DeleteObject(hDC); return; } r = org.x + strBaseW > dst.cols? dst.cols - org.x - 1 : strBaseW - 1; b = org.y + strBaseH > dst.rows ? dst.rows - org.y - 1 : strBaseH - 1; org.x = org.x < 0 ? 0 : org.x; org.y = org.y < 0 ? 0 : org.y; BITMAPINFO bmp = {0}; BITMAPINFOHEADER& bih = bmp.bmiHeader; int strDrawLineStep = strBaseW * 3 % 4 == 0 ? strBaseW * 3 : (strBaseW * 3 + 4 - ((strBaseW * 3) % 4)); bih.biSize=sizeof(BITMAPINFOHEADER); bih.biWidth=strBaseW; bih.biHeight=strBaseH; bih.biPlanes=1; bih.biBitCount=24; bih.biCompression=BI_RGB; bih.biSizeImage=strBaseH * strDrawLineStep; bih.biClrUsed=0; bih.biClrImportant=0; void* pDibData = 0; HBITMAP hBmp = CreateDIBSection(hDC, &bmp, DIB_RGB_COLORS, &pDibData, 0, 0); CV_Assert(pDibData != 0); HBITMAP hOldBmp = (HBITMAP)SelectObject(hDC, hBmp); //color.val[2], color.val[1], color.val[0] SetTextColor(hDC, RGB(255, 255, 255)); SetBkColor(hDC, 0); //SetStretchBltMode(hDC, COLORONCOLOR); strcpy(buf, str); const char* ln = strtok(buf, "\n"); int outTextY = 0; while(ln != 0) { TextOutA(hDC, 0, outTextY, ln, strlen(ln)); outTextY += singleRow; ln = strtok(0, "\n"); } uchar* dstData = (uchar*)dst.data; int dstStep = dst.step/sizeof(dstData[0]); unsigned char* pImg = (unsigned char*)dst.data + org.x * dst.channels() + org.y * dstStep; unsigned char* pStr = (unsigned char*)pDibData + x * 3; for(int tty = y; tty <= b; ++tty) { unsigned char* subImg = pImg + (tty - y) * dstStep; unsigned char* subStr = pStr + (strBaseH - tty - 1) * strDrawLineStep; for (int ttx = x; ttx <= r; ++ttx) { for (int n = 0; n < dst.channels(); ++n){ double vtxt = subStr[n] / 255.0; int cvv = vtxt * color.val[n] + (1 - vtxt) * subImg[n]; subImg[n] = cvv > 255 ? 255 : (cvv < 0 ? 0 : cvv); } subStr += 3; subImg += dst.channels(); } } SelectObject(hDC, hOldBmp); SelectObject(hDC, hOldFont); DeleteObject(hf); DeleteObject(hBmp); DeleteDC(hDC); }

呼叫demo如下:

void main()
{
	Mat img = imread("cat.jpg");
	if(!img.data)
	{
		cout<<"load image error"<<endl;
		return;
	}
	paDrawString(img, "測試漢字哈...\n換行了喲\n真的可以啊!!!~",Point(10, 10), Scalar(255,0,0), 50, true, true);
	imshow("img", img);
	waitKey();
}