如何创建具有特定模块宽度的位图？

如何创建具有特定模块宽度的位图？

在下面的代码中，您只需设置以毫米为单位的模块宽度和条码总高度。通过 optimizeToDPI 标志，您还可以为模块宽度添加优化（实际上会得到与 BCGetOptimalBitmapSize 相同的结果）。示例代码适用于线性条码，但也可适配二维码。

在 BCCreate (..) 之后调用此代码。

double moduleWidthUserMM = 0.26;
double heightUserMM = 22.0;
double dpi = 600;
int widthUserPx  = 1; // dummy value, since the width of the bar code is determined by the module width
int heightUserPx = dpi * heightUserMM / 25.4;  // for bitmaps we need [Pixel]
double width, height;
bool optimizeToDPI = TRUE; // adapt module width to next lower full Pixels => avoid quantization errors
int fontSizePt = (int)(0.51 + (10 * moduleWidthUserMM / 0.339)); // auto font size - works well with EAN / Code-128 / Code 39

// bounding rectangle of barcode -> desired drawing coordinates
RECT rect;
rect.left = 0;
rect.right = widthUserPx;
rect.top = 0;
rect.bottom = heightUserPx;

eCode = BCSetDPI(pBarCode, dpi, dpi);
eCode = BCSetIgnoreDpiFromDC(pBarCode, TRUE);

// Ensure that the width of a bar is a multiple of a single pixel (and at minimum one pixel)
eCode = BCSetOptResolution(pBarCode, optimizeToDPI);

// bar code should adapt to module width
eCode = BCSetSizeMode(pBarCode, e_SizeMode::eSizeMode_CustomModuleWidth);

// set module width in [0.001mm]
// we need a rounding delta of 0.001mm in case of optimize flag
eCode = BCSetModWidthN(pBarCode, moduleWidthUserMM * 1000 + (optimizeToDPI?1:0));

eCode = BCSetFontHeight(pBarCode, fontSizePt);

// Calculate bar code size
// for retrieving the size in [Pixel] we need a screen hDC
HDC hDC = GetDC(NULL);
eCode = BCGetBarcodeSize(pBarCode, &rect, hDC, eMUPixel, &width, &height);
if (hDC)
  DeleteDC(hDC);

// Save bitmap with the given module width and size
eCode = BCSaveImage(pBarCode, "C:\\Temp\\Barcode-600dpi.jpg", eIMJpg, (int) (width + 0.5), (int) (height + 0.5), dpi, dpi);