Zoom the picture within the picturebox of Visual Studio C++ - c++

Question

I have a problem about zooming into the picture displayed in a picturebox Picture Control. The expected result is similar to the following link: A scrollable, zoomable, and scalable picture box. The picture is zoomed in within the picturebox. Note the picturebox is zoomed in.
However, this can be implemented in .NET Framework 2.0. I have searched some information on the Internet, but none used C/C++ Windows API of Visual Studio. How can I zoom a picture within a the picturebox Picture Control when I work on Windows Forms of Visual Studio C++ 2010. Thank you for anyone's reply.

Answer 1

I have faced the same issue and I searched a lot but didn't get the solution in cpp(freely available in c# and VB).
So finally i decided to implement it by my own. If your Image size is bigger than the picture box then only 1 level of zoom(original size of image) you can do with my implementation.
I will help you with the implementation. In current implementation
if you do left click of mouse it will ZoomIn and
if you do right click of mouse it will ZoomOut.
Assuming you have read the image file(.png, .jpg, .bmp, ...) in bmpPicture.
Bitmap ^bmpPicture = gcnew Bitmap(strFilename);// if not it can help
private: System::Void pictureBox1_Click(System::Object^ sender, System::EventArgs^ e) {
MouseEventArgs ^ms = (MouseEventArgs^)e;
if (ms->Button == System::Windows::Forms::MouseButtons::Left)
{
int pbx = ms->X;
int pby = ms->Y;
int img_x = (pbx * mwidth / pbwidth * 1.0f);
int img_y = (pby * mheight / pbheight * 1.0f);
pictureBox1->Location = System::Drawing::Point(pbx - img_x, pby - img_y);
pictureBox1->SizeMode = PictureBoxSizeMode::AutoSize;
pictureBox1->Image = bmpPicture;
}
else if(ms->Button == System::Windows::Forms::MouseButtons::Right)
{
int pbx = ms->X;
int pby = ms->Y;
pictureBox1->Location = System::Drawing::Point(0, 0);
pictureBox1->SizeMode = PictureBoxSizeMode::StretchImage;
pictureBox1->Image = bmpPicture;
}
}
Hope this will help you...

Answer 2

Without any source code, it is difficult to comment.
StackOverflow is for problem solving; we can troubleshoot your starting code and get it working and during the course of which we can also fine tune design.
Anyway, I would like to give some pointers:
One or two picture boxes: entirely depends on your UI requirement.
Showing full or partial region of an image: StretchBlt is a powerful
API that can be used to achieve. See MSDN documentation for details.
Which class to use for picture box: if MFC is being used, then
derive a class from CStatic, overload the OnPaint() and use
StretchBlt to paint the image.
Classes to use for image: CBitmap, CImage, Gdiplus::Image.
Each have their own pros and cons.
If transparent images/PNGs are to be suported, better go for CImage or Gdiplus::Image.
You can get enough info here: CBitmap CImage Gdiplus::Image
Hope this would give you some starter.