关于pictruebox载入图片问题

[rabemay]

怎样让载入的图片按pictruebox的大小缩放显示（不要让我用image）

[supergreenbean]

StretchBlt API

[supergreenbean]

方便点,这样也可以:

Option Explicit
Private m_oMyPic As IPictureDisp
Private Sub Form_Load()
    Picture1.AutoRedraw = True
    Set m_oMyPic = LoadPicture("c:\mypic.jpg")
    Set Picture1.Picture = m_oMyPic
End Sub

Private Sub Form_Resize()
    With Me
        Picture1.Move 0, 0, .ScaleWidth, .ScaleHeight
    End With
End Sub

Private Sub Picture1_Resize()
    Picture1.PaintPicture m_oMyPic, 0, 0, Me.ScaleWidth, Me.ScaleHeight
End Sub

[东方之珠]

'以下代码仅供参考
'将picture1中的图片缩放为picture2的宽度和高度后，保存为文件 D:\001.bmp

Option Explicit
'Form1上添加一个Command1,2个图片框picture1,picture2
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
Private Declare Function SetStretchBltMode Lib "gdi32" (ByVal hdc As Long, ByVal nStretchMode As Long) As Long
Private Const HALFTONE = 4
Private Const SRCCOPY = &HCC0020 ' (DWORD) dest = source

Private Sub Command1_Click()
        Dim Rtn As Long
        Dim hDC1 As Long, hDC2 As Long
        hDC1 = Picture1.hdc
        hDC2 = Picture2.hdc
        Call SetStretchBltMode(hDC2, HALFTONE)
        Rtn = StretchBlt(hDC2, 0, 0, Picture2.ScaleWidth, Picture2.ScaleHeight, hDC1, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, SRCCOPY)
        SavePicture Picture2.Image, "D:\001.bmp"
        
End Sub

Private Sub Form_Load()
        Me.ScaleMode = 3
        Picture2.AutoRedraw = True
        Picture1.Picture = LoadPicture("C:\TT.BMP")
End Sub

[rabemay]

我用的是vb 6.0

[supergreenbean]

上面的都是VB6代码,只是为了看起来漂亮,所以用了代码格式化

[wuzhicheng5]

       
        //表示图片
        private Image img;
        //比率
        private float ratio = 1F;
        //图片被表示的范围
        private Rectangle imgRect;

        private void PicShow_Load(object sender, EventArgs e)
        {
            string path = @"E:\wxy\3.jpg";
            img = Image.FromFile(path);
            //this.Show(im);
           
            imgRect = new Rectangle(0, 0, img.Width, img.Height);
            ratio = 1F;
            //表示图片
            picBox.Invalidate();
        }
        
        //PictureBox1的MouseDown事件处理器
        private void picBox_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            PictureBox pb = (PictureBox)sender;
            //被点击的位置变换为图片上的位置
            Point imgPoint = new Point(
                (int)Math.Round((e.X - imgRect.X) / ratio),
                (int)Math.Round((e.Y - imgRect.Y) / ratio));

            //变更比率
            if (e.Button == MouseButtons.Left)
            {
                ratio *= 2F;
            }
            else if (e.Button == MouseButtons.Right)
            {
                ratio *= 0.5F;
            }

            //计算图片的表示范围
            imgRect.Width = (int)Math.Round(img.Width * ratio);
            imgRect.Height = (int)Math.Round(img.Height * ratio);
            imgRect.X = (int)Math.Round(pb.Width / 2 - imgPoint.X * ratio);
            imgRect.Y = (int)Math.Round(pb.Height / 2 - imgPoint.Y * ratio);

            //表示图片
            picBox.Invalidate();
        }

        //PictureBox1的Paint事件处理器
        private void picBox_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
        {
            if (img != null)
            {
                //在被指定的范围表示图片
                e.Graphics.DrawImage(img, imgRect);
                picBox.SizeMode = PictureBoxSizeMode.CenterImage;
            }
        }