Question

This might be an odd question, but when I scale my image in C# I need it to be pixelated and not anti-aliased. Just like in MSpaint when you scale.

I hope images anti-alias by default in C#, or else I changed something I didn’t want to.

I’ve tried playing around with the Graphics.InterpolationMode but no luck there. I’m using a Bitmap object to hold the image and it’s being constructed like so:

// A custom control holds the image this.m_ZoomPanPicBox.Image = new Bitmap(szImagePath); 

And a brief synapsis of the custom control:

class ZoomPanPicBox : ScrollableControl {     Image m_image;     float m_zoom = 1.0f;     InterpolationMode m_interpolationMode;     ...     ////////////////////////////////////////////////////////     public ZoomPanPicBox()     {         //Double buffer the control         this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.ResizeRedraw | ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);          this.AutoScroll=true;     }     ////////////////////////////////////////////////////////     protected override void OnPaint(PaintEventArgs e)     {         //if no image, don't bother         if(m_image==null)         {             base.OnPaintBackground(e);             return;         }          //Set up a zoom matrix         Matrix mx = new Matrix(m_zoom,0,0,m_zoom,0,0);          //now translate the matrix into position for the scrollbars         mx.Translate(this.AutoScrollPosition.X / m_zoom, this.AutoScrollPosition.Y / m_zoom);          //use the transform         e.Graphics.Transform = mx;          //and the desired interpolation mode         e.Graphics.InterpolationMode = m_interpolationMode;          //Draw the image ignoring the images resolution settings.         e.Graphics.DrawImage(m_image,new Rectangle(0,0,this.m_image.Width,this.m_image.Height),0,0,m_image.Width, m_image.Height,GraphicsUnit.Pixel);          base.OnPaint(e);     } 

Any ideas? Thanks.

Answer 1

Actually, you’re right with InterpolationMode, as the docs say. Just set it to InterpolationMode.NearestNeighbor. In your code sample, you never set m_interpolationMode.