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Blending rasterized images

You can blend the stroke and fill values of the selected rasterized objects or bitmap images with the stroke and fill values of background objects present on the same layer. The Plazmic® Composer calculates the fill and stroke values of the overlapping portions of the selected objects and the background objects based on the blending method you choose. To apply a blending method, you must rasterize an object.

The Plazmic Composer calculates the blended color values by combining the values of the red, green, and blue (RGB) color channels for each pixel where the rasterized image and the underlying object(s) overlap. For example, suppose you create and rasterize a rectangle with a fill value of RGB 127, 0, 0 (dark red) that overlaps another rectangle with a fill value of RGB 127, 127, 0 (olive green). By applying the Subtract blending method to the dark red rectangle, the RGB values of the overlapping section change to RGB 0, 0, 0 (black). If you apply the Add method, the RGB values of the overlapping section will be RGB 255, 127, 0 (orange).

The Plazmic Composer actually calculates these RGB values using the range 0 to 1 rather than 0 to 255. The only method where this makes a difference is the Multiply method. Using the same example, the dark red rectangle would have RGB values of 0.5, 0, 0, and the olive green rectangle 0.5, 0.5, 0. Multiply those three sets of values together and the result is 0.25, 0, 0, which is equivalent to 63, 0, 0 (darker red).

You can apply one of the following blending methods to any rasterized object or bitmap image:

Blending method

Effect

Example

Normal

None (no blending method applied).

 

Multiply

The RGB values of the object and the underlying object(s) are multiplied together for each of the three channels.

 

Screen

The selected object “burns through” underlying objects. This has no effect on the background color.

 

Erase

The selected object is removed from the canvas. If an object is underneath the bitmap object, the shape of the bitmap object might create the effect of a “cut-out” on the underlying object.

 

Add

The RGB values of the object and underlying object(s) are added for each of the three channels.

 

Subtract

The RGB values of the underlying object(s) are subtracted from the object’s values for each of the three channels.

 

Darkest

The lower of the two RGB values is used for each of the three channels.

 

Lightest

The higher of the two RGB values is used for each of the three channels.

 

Difference

The difference between the object’s and the underlying object(s) RGB values is used for each of the three channels.

 

Average

The average of the object’s and the underlying object(s) RGB values is used for each of the three channels.

 

Invert

The object’s alpha level is used to invert the underlying objects.

 

Dissolve

A random pattern is created based on the opacity of each pixel.

Tip: When using the Dissolve blending method, you must set the opacity level of the object to see the effect.

 

Replace Hue

The hue of the object is used on the underlying object(s).

 

Replace Saturation

The saturation of the object is used on the underlying object(s).

 

Replace Luminosity

The luminosity of the object is used on the underlying object(s).

 

Replace Color

The hue and saturation of the object is used on the underlying object(s).

 

XOR Mask

The difference of the object opacities is computed, the absolute value is determined, and the dominant color displays.

 

Alpha Mask

This option is the inverse of an erase. The composited object shape is used to mask out all lower objects.

 

Index


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