User Documentation
Filter Brush is a drawing plugin that lets you "draw" filters (like blurring, sharpening, etc.) using custom brushes with dynamic behavior that changes the settings of the brush as you draw. It's useful for making filtering effects like depth of field or slight distortions, as well as simulating dodge, burn, and similar tools.
After putting the BrushFilter.dll file in the Effects folder of your Paint.NET installation, you will see it appear under the Effects → Tools menu.
When you use the plugin, it will load in full-screen mode. The version of the plugin is listed at the top of the screen so you know which version you're using.
The white rectangle is called the canvas. The cursor is hidden when you hover over the canvas, and a rectangle is displayed instead. This rectangle indicates how large a brush stroke will be.
At the bottom of the screen is the help bar, which describes what everything does. If you forget what something does, just hover the mouse over that object and read the text at the bottom.
On the right side of the screen is the settings. The top of the settings is divided into three buttons called tabs, and each one has its own settings you can play with.
To draw with the brush, left-click and hold down the mouse while moving it. To stop drawing, release the button. If you are zoomed in and try to draw beyond the visible screen, the image will automatically pan for you. The rectangular brush region is hidden when drawing.
To move the image around when zoomed in, hold control and click the left mouse button and hold it down while moving the mouse. Alternatively, click and hold the middle mouse button to pan. To stop panning, release the mouse button.
If you make a selection before opening the plugin, you will see that selection as a light area with all the non-selected pixels darkened. Anything you draw in the darkened area will not be applied when you apply the plugin, since only the selected pixels are affected. The white area in the image below is the selected area.
You can right-click the canvas to open a dialog that lets you set the color of the white rectangle. It can be transparent, white, black, or replaced by the image on the clipboard.
Tip When working with multiple layers, to see the layers underneath the current layer, merge them down before opening the plugin, copy the merged layer, and undo the merge. Now that it's on the clipboard, open the plugin and right-click to set the image on the clipboard. You can now see the layers underneath the current layer.
Each tab has its own settings.
Controls: This tab is open when you first open the plugin. It displays basic settings, like the brush to use and the buttons to cancel or accept all changes.
Effect: This tab lets you select the effect you want to apply from a drop-down list. All built-in effects are supported, and custom effects are automatically loaded from the paint.net Effects folder.
Jitter: This tab contains settings to change the brush behavior any time the mouse moves while drawing.
Other: This tab contains a lot of very useful tools that aren't used often, like drawing with symmetry or drawing with a minimum distance between each brush stroke.
Canvas Zoom: This is how far zoomed in the current image is. 100% is normal. Larger values mean you've zoomed in much closer to the image and smaller values mean you've zoomed away.
Tip You can hold Ctrl while moving the mouse wheel up and down to scroll in and out; respectively.
Brushes: This box shows a picture of the current brush you use to draw with. If you click the box, it shows a list of all the brushes you have loaded that you can use. At the bottom of the list is a button called "Add Brushes". Clicking on that opens a dialog box that lets you browse your computer for images to add to the brushes. When images are added, they appear at the bottom of the list, with "Add Brushes" at the very end.
Tip If a brush is added without any transparency in it, the brightness of the image will be used to compute transparency, which works well with black-and-white images. If there is any transparency at all, the existing transparency will be used instead.
Effect Intensity: When you draw with the brush, this determines how much of the effect is applied. At 100% intensity, the effect is applied in full, but it can be toned down so the affected image and the original image are mixed together, making the intensity of the effect more subtle. At 0% intensity, the original image remains unchanged.
Tip You can hold Ctrl + I while moving the mouse wheel up and down to increase and decrease the intensity of the effect; respectively.
Brush Rotation: This is the tilt of the brush, which goes from -180 to 180 degrees. Negative tilt rotates the image counter-clockwise and positive tilt rotates it clockwise.
Tip You can hold Ctrl + R while moving the mouse wheel up and down to tilt the brush counter-clockwise and clockwise; respectively.
Brush Size: This determines how large the brush is (in pixels). You can see this by hovering the mouse over the canvas and looking at how large the rectangle is.
Tip You can hold Ctrl + S while moving the mouse wheel up and down to increase and decrease the brush size; respectively.
Undo and Redo: Each brush stroke is saved as an image to a temporary location on your computer. Once you have made a brush stroke by clicking and releasing the mouse, you may undo that stroke. Any brush stroke you undo can be redone with redo, but if you make a new brush stroke after undoing old ones, those ones are lost and cannot be redone.
Tip You can press Ctrl + Z to undo a brush stroke and Ctrl + Y to redo one.
Ok and Cancel: Once you're done with the plugin, click the Ok button to apply all changes from the plugin and close it. Click cancel to discard those changes instead. You can also press enter if the Controls tab is active to apply the plugin, or escape to cancel it. All settings are saved between uses of the plugin when changes are saved.
The active effect is shown with an icon (if it has one) in the drop-down menu at the top of the Effect tab. The settings of the effect appear below it and function like most built-in paint.net effect settings.
Overwrite Mode: Usually, the effect is drawn on a transparent screen that is merged on top of the original when you stop drawing. In overwrite mode, the effect replaces the pixels on the original canvas instead. This is useful e.g. when you want to blur over transparent areas, and when you're working on a transparent canvas in general.
Every time the mouse moves as you draw, a number between 0 and the displayed value for one of these settings is generated. That number is used to change the default setting. This has the effect of visually 'jittering' the brush as you draw.
Random Min Size: As you draw, the size of your brush is randomly reduced by the number generated from 0 to the shown value.
Random Max Size: As you draw, the size of your brush is randomly increased by the number generated from 0 to the shown value.
Random Rot to Left: As you draw, the brush is randomly tilted counter-clockwise by an amount of degrees equal to the number generated from 0 to the shown value.
Random Rot to Right: As you draw, the brush is randomly tilted clockwise by an amount of degrees equal to the number generated from 0 to the shown value.
Random Min Intensity: As you draw, the effect is randomly made less intense by the % equal to the number generated from 0 to the shown value.
Random Max Intensity: As you draw, the effect is randomly made more intense by the % equal to the number generated from 0 to the shown value.
Horizontal Spray: As you draw, the brush is horizontally translated by some % of pixels equal to the number generated from 0 to the shown value. It acts like a horizontal spray can.
Vertical Spray: As you draw, the brush is vertically translated by some % of pixels equal to the number generated from 0 to the shown value. It acts like a vertical spray can.
Size Shift: Every time the mouse moves as you draw, the size of the brush is increased or decreased by the chosen amount. When the size of the brush is as large as allowed, it begins to shrink, and vice versa.
Rotation Shift: Every time the mouse moves as you draw, the brush tilts by the chosen amount. It tilts clockwise if the amount is positive, or counter-clockwise instead. It can tilt indefinitely in one direction.
Intensity Shift: Every time the mouse moves as you draw, the intensity of the brush increases or decreases by the chosen amount. If it becomes fully intense, it begins to become less again, and vice versa.
Minimum Draw Distance: The mouse must move a certain number of pixels away from the last position that the brush was applied at in order to apply the brush again. This has the effect of making dotted trails as the mouse moves.
Rotate With Mouse: When this checkbox is active, the current brush will be rotated to follow the motion of the mouse. It's assumed that if the image looks like it points somewhere that it must point to the right for this to work properly. If the image doesn't point to the right, change the brush rotation under the Controls tab until it does.
Symmetry: You can set symmetrical drawing on so that as you draw, your drawings are mirrored across the horizontal and/or vertical axes. It makes drawing symmetrical objects, like butterflies, much easier.
Clear Custom Brushes: Clicking this button will discard all brushes that you have added. If you use the option to automatically add images from select locations when the plugin starts, it will not change that setting.
Clear Settings: Clicking this button will discard all settings saved between uses of the plugin and revert them to their original values. Use this if you make a change in the settings and can't find it, or if you want to start over.
Brush Smoothing: This setting controls how anti-aliasing is applied to each brush stroke. When you click on the button, a list drops down with options to choose the anti-aliasing amount. Higher amounts increase the amount of blur around the edges (also called anti-aliasing) to prevent a jagged appearance. The jagged option uses no anti-aliasing, so edges may appear jagged if the brush has sharp edges.
Custom Brush Locations: Clicking this button opens a dialog box that allows you to define locations to look for brushes when the plugin loads. All images specified will be loaded if possible, and images from each directory will be loaded if possible. Loading large amounts of images can lead to lag when the plugin is opened.
Preferences Dialog: This is the dialog that opens when the Custom Brush Locations button is clicked. It has a textbox where you can type in brush locations. Alternatively, you can click 'Add Folder' to add a directory to search through for images when the plugin loads. All images found will be added to the list of brushes if possible.
Load Default Brushes?: In the preferences dialog, if this is checked, the plugin will load default brushes when it begins. If no custom brushes are loaded and default brushes are not loaded, the circle brush will be loaded anyway.
