Center Lines (updated on 2023/10/29, with GPU drawing)

[ReMake]

This plugin is the result of discussion.

You can find it: Effects -> Tools -> Center Lines

 

Download from my PluginPack (obsolete version)

 

For paint.net 5.0.11+

 

This plugin allows you to draw centerlines of various widths on the added layer in the center of the canvas or in the center of the selected area. You can also change the center of centerlines relative to the canvas or relative to the selected area. The Color's drop-down list allows you to select a line color: Primary, or Secondary, or Custom.

 

Source code for CodeLab

Spoiler

// Name:Center Lines
// Submenu:Tools
// Author:ReMake
// Title:Center Lines
// Version:2.0
// Desc:Drawing auxiliary center lines
// Keywords:paint.net|effect|center|lines
// URL:https://www.getpaint.net/redirect/plugins.html
// Help:
#region UICode
IntSliderControl lineWidth = 1; // [1,50] Line Width
ListBoxControl color = 0; // Color|Primary|Secondary|Custom
ColorWheelControl custom = ColorBgra.FromBgra(0, 0, 255, 255); // [Red?] {color} 
PanSliderControl position = new Vector2Double(0.000, 0.000); // Position
#endregion

protected override unsafe void OnDraw(IDeviceContext deviceContext)
{
    deviceContext.DrawImage(Environment.SourceImage);  // preserve background

    RectInt32 selection = Environment.Selection.RenderBounds;
    ColorBgra32 primaryColor = Environment.PrimaryColor;
    ColorBgra32 secondaryColor = Environment.SecondaryColor;
    ColorBgra32 lineColor = ColorBgra.Red;
    // converts the PanSlider values to between 0 and 1
    double posX = (position.X + 1) / 2;
    double posY = (position.Y + 1) / 2;
    // shift of lines by 1 pixel to the right/down if posX/posY = 0
    int shiftX = posX == 0 ? 1 : 0;
    int shiftY = posY == 0 ? 1 : 0;
    // converting posX/posY to actual pixel coordinates
    int centerX = (int)Math.Round(selection.Width * posX) + selection.Left + shiftX;
    int centerY = (int)Math.Round(selection.Height * posY) + selection.Top + shiftY;

    switch (color)
    {
        case 0:
            lineColor = primaryColor;
            break;
        case 1:
            lineColor = secondaryColor;
            break;
        case 2:
            lineColor = custom;
            break;
    }

    ISolidColorBrush brush = deviceContext.CreateSolidColorBrush(lineColor);

    deviceContext.AntialiasMode = AntialiasMode.Aliased;

    deviceContext.DrawLine(
    centerX, selection.Top,
    centerX, selection.Bottom,
    brush, lineWidth);
    deviceContext.DrawLine(
    selection.Left, centerY,
    selection.Right, centerY,
    brush, lineWidth);
}

 

 

The effect script is written based on an example from @BoltBait's CodeLab Help tutorial. Thanks @BoltBait for his amazing CodeLab Help.

 

CenterLines.zip

Edited October 30, 2023 by ReMake
Added CodeLab script

[HyReZ]

Thank you sir!

[Pixey]

That looks cool @ReMake - thank you

[Seerose]

 @ReMake!

 

Thanks you for this tutorial.   New is always better.  

I have a Center Line plugin. When I click on it does not show which author it is from. 

[ReMake]

33 minutes ago, Seerose said:

...which author it is from. 

 

@Enormator author of previous plugins (see my comment).

[Seerose]

@ReMake!

 

The old plugin is now deleted anyway.
Yours is much better because you can choose color. 👍
Again many thanks for your effort. 

[lynxster4]

Thank you @ReMake!  This will come in handy.    🍰

 

[ReMake]

The effect has been updated for paint.net 5.0.11+. Added a Line Width control and the ability to change the transparency of lines in Custom mode. The effect has been converted to take advantage of GPU capabilities.

Download it from the first post.

[Pixey]

26 minutes ago, ReMake said:

The effect has been converted to take advantage of GPU capabilities.

 

Thank you @ReMake

[lynxster4]

Thank you @ReMake The line width control makes a big difference!  😊

[Welsh Yellow Cheddar]

@ReMake Thanks, very interesting for marking or delimiting sections.

 

Could diagonals be added?

Dashed lines with options to adjust the gap between the length of dashes would be great as well.

Dots?

Sorry if I ask too much. They are things I can use.

 

[ReMake]

6 hours ago, Welsh Yellow Cheddar said:

Could diagonals be added?

Dashed lines with options to adjust the gap between the length of dashes would be great as well.

Dots?

 

An interesting suggestion. If I have enough free time and my coding knowledge is enough, I will try to implement your suggestions. Now I'm focused on updating my previous plugins.