为什么用picturebox放大图像到一定比例图像就出错了？

[bonol]

放大的语句
Picture2.PaintPicture Picture2.Picture, 0, 0, yk * bl, yg * bl, 0, 0, yk, yg’bl是放大比例
放大到400％时图像的底部就重复了，500％时就不放大了，什么原因？如何判断一幅图像的最大放大比例？

[kmzs]

picturebox的大小有限制

[海牛]

用StretchBlt函数
Option Explicit

Private Declare Function StretchBlt Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal nSrcWidth As Long, ByVal nSrcHeight As Long, ByVal dwRop As Long) As Long

StretchBlt Me.Picture2.hdc, 0, 0, 200, 200, Me.Picture1.hdc, 100, 100, 50, 50, vbSrcCopy

[wumy_ld]

用BitBlt函数
Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long