16.16. Glowing Hot

16.16.1. Overview

Figure 16.377. Example for the Glowing Hot filter

Example for the “Glowing Hot” filter

The Glowing Hot filter

Example for the “Glowing Hot” filter

The Glowing Hot logo

This filter adds a glowing hot metal effect to the alpha (that is to these areas of the active layer defined by the non-transparent pixels).

The filter is derived from the Glowing Hot script (FileCreateLogosGlowing Hot in the image window), which creates a glowing text logo (see above).

The filter simulates a red-hot, a yellow-hot, and a white-hot area - each color representing a different metal temperature -; the alpha's outline shines through the glowing.

[Warning] Warning

The image will always be resized to the active layer's size.

16.16.2. Activate the filter

This filter is found in the image window menu under FiltersAlpha to LogoGlowing Hot.

The filter only works if the active layer has an alpha channel. Otherwise, the menu entry is insensitive and grayed out.

16.16.3. Options

Figure 16.378. Glowing Hot options

“Glowing Hot” options

Effect size (pixels * 3)

This is actually the font size option of the Glowing Hot logo. The value is used to calculate the size of the feathering border (cf Section 4.9, “Feather”) before the alpha is filled with red, yellow, and white. These feathered colors make the hot metal effect.

Figure 16.379. Effect size examples

Effect size examples

Effect size 50

Effect size examples

Effect size 350

Background color

This is the color used to fill the Background layer; it defaults to black (7,0,20). Click on the button to open a color selector, if you want to choose a different color.

16.16.4. Filter details

To create the glowing effect (red-hot, yellow-hot, and white-hot area), the alpha is feathered and then filled with the respective color, from red to white with decreasing feather sizes and color intensities in the feathered area.

The illustration below shows the hot metal colors and the width of the feathering border in percent of Effect size (these are the values the filter actually uses).

Figure 16.380. Effect size

Effect size

Glowing hot metal colors and their relative feather sizes

In the example images you can see how the alpha's outline shines through the glowing. This is achieved with a alpha filled with black as top layer, where the layer mode is set to overlay. Using a black overlay layer won't change pure white, but darkens light colors at the alpha's edges so that the outline appears.