dc rectangleVB中，谁能帮我解释一下下面这句话中。每个词都是什么意思？

隔离型dcdc和非隔离型dcdc有什么不同

DC/DC 模块是直流-直流变压,所谓隔离和非隔离，是指在整流滤波后是否加变压器， 加变压器的为隔离 ,不加变压器的为非隔离,一般的电源都是隔离的， 隔离的安全性更高 ,对设计而言，隔离的使用的器件的要求会更低,因为隔离的经过变压器降压后送到电源模块的,非隔离是直接通过220v送给电源模块的,现在的电源芯片都是隔离的

Bitmap改变大小

用StretchBlt可以放大或缩小bitmap The StretchBlt function copies a bitmap from a source rectangle into a destination rectangle, stretching pressing the bitmap to fit the dimensions of the destination rectangle, if necessary. The system stretches presses the bitmap ording to the stretching mode currently set in the destination device context. BOOL StretchBlt( HDC hdcDest, // handle to destination DC int nXOriginDest, // x-coord of destination upper-left corner int nYOriginDest, // y-coord of destination upper-left corner int nWidthDest, // width of destination rectangle int nHeightDest, // height of destination rectangle HDC hdcSrc, // handle to source DC int nXOriginSrc, // x-coord of source upper-left corner int nYOriginSrc, // y-coord of source upper-left corner int nWidthSrc, // width of source rectangle int nHeightSrc, // height of source rectangle DWORD dwRop // raster operation code );

VB中，谁能帮我解释一下下面这句话中。每个词都是什么意思？

你可以查下MSDN，上面有函数原型BOOL BitBlt( HDC hdcDest, // handle to destination DC int nXDest, // x-coord of destination upper-left corner int nYDest, // y-coord of destination upper-left corner int nWidth, // width of destination rectangle int nHeight, // height of destination rectangle HDC hdcSrc, // handle to source DC int nXSrc, // x-coordinate of source upper-left corner int nYSrc, // y-coordinate of source upper-left corner DWORD dwRop // raster operation code);以及各个参数说明Parameters：hdcDest [in] Handle to the destination device context. nXDest [in] Specifies the x-coordinate, in logical units, of the upper-left corner of the destination rectangle. nYDest [in] Specifies the y-coordinate, in logical units, of the upper-left corner of the destination rectangle. nWidth [in] Specifies the width, in logical units, of the source and destination rectangles. nHeight [in] Specifies the height, in logical units, of the source and the destination rectangles. hdcSrc [in] Handle to the source device context. nXSrc [in] Specifies the x-coordinate, in logical units, of the upper-left corner of the source rectangle. nYSrc [in] Specifies the y-coordinate, in logical units, of the upper-left corner of the source rectangle. dwRop [in] Specifies a raster-operation code. These codes define how the color data for the source rectangle is to bined with the color data for the destination rectangle to achieve the final color. 以及函数的返回值：Return ValuesIf the function eeds, the return value is nonzero.If the function fails, the return value is zero. 遇到不明白的，多查查MSDN，基本都能找到各个函数声明及使用 以上答案 希望对你有帮助