OpenCV實現影象上新增漢字
阿新 • • 發佈:2018-11-08
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();
}