Pena Contents
Control Pane
Brush Pane
Texture Pane
Effects Pane
Color Picker
Save/Load Pane
Selection Pane
Preferences Pane
Intelligent Canvas
Wacom Bluetooth Stylus
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The Effects Library
Effects Introduction
Color Source Effects
  • Color Source Introduction
  • Color
  • Color, Clock
  • Color, HSBA Mask
  • Color, RGBA Mask
  • Drawing
  • Drawing, Blur
  • Drawing, Edge Detect
  • Drawing, Emboss
  • Drawing, Oil
  • Drawing, Pixelate
  • Drawing, Ripple
  • Drawing, Rotate
  • Drawing, Twist
  • Texture
  • Texture, Blur
  • Texture, Edge Detect
  • Texture, Emboss
  • Texture, Oil
  • Texture, Pixelate
  • Texture, Ripple
  • Texture, Rotate
  • Texture, Twist
    Procedural Source Effects
    Color Filter Effects
    Spatial Filter Effects
    Math and Logic Effects
    Special Effects
    Artists Gallery
    The Artist Gallery
    Pena Support


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      Effect:Drawing Edge Detect
      Category:Color Sources

      Description: The Drawing Edge Detect Effect lets you use your 'most recent' drawing as the color source with an added edge detection.

      The Drawing Edge Detect Effect is identical to the Drawing Effect with the addition of an edge detection. This allows you to have very accented edges, or only view the edges of an image.

      Note that Drawing Edge Detect outputs a two-color image. It uses the incoming Color 1 for the Non-Edge color and the incoming Color 2 for the Edge Color.

      If you enable the Fit To Brush Option you will paint with the Current Edge Detected Drawing sized to your brush.


      You might want to also watch the Pena Tutorial #7 - Using the 'Drawing' Texture video tutorial.

      Under normal use, each time you stop painting on the Canvas (eg., lift your finger) the current Canvas is stored in a special texture called the Drawing Texture.

      You can change this behavior using the Drawing Control icon on the Control Pane. You can turn off the automatic saving of the Canvas into the Drawing Texture, and instead specify manually when you want the Drawing Texture updated.

      Leaving Drawing on automatic update allows you to paint with 'feedback'. Each time you start painting, what you painted last will be used as input to what you are painting now.

      Putting Drawing on manual update lets you treat the last Canvas stored in the Drawing Texture as a more permanent texture, not changing each time you paint.

      Also keep in mind that unlike other Textures, which automatically orient to the device orientation, the Drawing Texture, because it is a copy of the Canvas, does not auto-orient, but stays in the original orientation it was created in.

      Options: The Drawing Edge Detect Effect has the following Options Pane:

      Edge Threshold:This controls the sensitivity of the edge detection. Larger values detect fewer edges, smaller values detect more edges.
      Fit To Brush:If set to a Red X the Effect spans the screen such that as you paint you reveal the Effect. When set to a Green Check Mark the Effect is sized to the brush such that as you paint the entire Effect is within the brush itself.
      Output Color 1:By default this is set to REPLACE which means that the set color will be output to Color 1. You can change this as explained in Options Pane Color Mixers.
      Output Color 2:By default this is set to IGNORE which means that the Color 2 will be ignored (the original Color 2 will be kept). You can change this as explained in Options Pane Color Mixers.

      Example: To show a use for the Drawing Edge Detect Effect we started by placing our orchid photo into the Drawing buffer. The photo looks like this:

      We then set the Edge Threshold to .6, a rather high value, and generated this edge detected result:

      You can see, in the image above, that only the strongest edges were detected using .6 as the Threshold.

      In the next image, we have used two Effects. We start with the Drawing Effect in Slot 1, and the Drawing Edge Detect in Slot 2 with our .6 Threshold and Output Color 1 set to MULTIPLY. This will Multiply the original image with the edge detected image. Look closely at what we get - and compare it with the original above:

      See how the orchid flowers themselves seem punched out, more accentuated, with the rest in more of a background.

      In the next image our Threshold is set to the default of .1:

      And here is the result of it, multiplied with the original Drawing (Output Color 1 set to Multiply):

      We get a more distorted effect because there are far more edges.

      Keep in mind that our results were done using Color 1 set to white and Color 2 set to black. You can send any colors in to get totally different effects. Since our edge color was black (Color 2), the effects we achieved were due to black multiplied times anything is black.


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