Interface 



1

Background (pull down menu Select Background)
You can either select a uniform background color (Select Color button) with the help of an interactive color selection tool, or an image file (Select Image button). Note that you can also drag and drop an image directly from a file manager to the Background zone.

2

Foreground (pull down menu Select Foreground)
You can either select a uniform foreground color (Select Color button) with the help of an interactive color selection tool, or an image file (Select Image button). Note that you can also drag and drop an image directly from a file manager to the Foreground zone.

3

Resulting image
This part displays the resulting image.
You can drag and drop this image into the Background zone as a new background image. It allows doing successive transparency effects without saving the intermediate steps.

4

Transparency
This part contains the interactive control for the transparency rate (from 0% for an opaque foreground to 100% for the absence of a foreground). The transparency result is displayed for the selected foreground image or color on a contrast card (juxtaposition of a perfectly black and a perfectly white background).
The transparency mode can be modified either by using the pull down menu Transparency Mode or by clicking on the corresponding button.

Transparency Modes 


Direct Uniform Transparency

The transparency effect is directly applied on the selection with the chosen transparency rate.

Inverse Uniform Transparency

The transparency effect is removed with the chosen transparency rate. The operation is performed with the same parameters for all the selected pixels. It can give invalid pixels which can be displayed in a color (red in the following example) selected by the user in the settings.

Inverse Non Uniform Transparency

The operation is performed independently for each pixel. A parameter allows monitoring the removal of the transparency effect. The maximum removal corresponds to the limit before the pixel becomes invalid.

Visualize Removal Part

This option allows seeing the removal part on a chosen background.

Select Expected Background

The user can select zones and then the expected background color for these zones. The software computes the foreground color which, when applied to the average pixel color of the selected zones, ensures the best match with the color selected by the user.

Program Features 


From subtractive to additive transparency



With the side bar you can modify the transparency effect from subtractive transparency (0%) to additive (100%) transparency.

Transparency as generalized f-mean



By clicking on the various buttons of the grid, you can change the selected function and you can change the parameter “p” by writing the value in the text area or with the slide bar.

By clicking on the middle of the grid, you enter in a new mode in which you can select five different logarithm functions.



Translucency by a scattering layer



In this program, the unit thickness layer reflection is described as the combination of a proportion of the opaque foreground and an achromatic part. The colored bars indicate impossible configurations. If the foreground is an image, some pixels can be invalid for the chosen parameters.

In this program, the transparency rate is tuned by the relative layer thickness from 0 (transparent) to infinite (opaque).



When the option “Non-scattering layer” is selected, the foreground corresponds to the reflection of the unit thickness layer on a perfect white background. The infinite thickness layer gives rise to no reflection therefore a black color whatever the background.

Mouse Options 


When the mouse pointer is over the modified image, the position (X,Y) and the color (R,G,B) of the pixel are displayed.

- Left Click outside a selected zone: create a new rectangular zone

- Left Click inside a selected zone: move the selected zone within the background

- Double Click: apply the selected transparency on the whole background

- Right Click: open the following pull down menu

Inside a selected zone, a right-click enables to modify the selected zone by adding, moving or removing an edge point.

Settings 


The settings can be modified by using the pull down menu Help/Settings

A border can be applied or removed around each selection with the option “Show Selections Borders”.

In inverse uniform transparency mode, the invalid pixels can be marked with the option “Highlight Invalid Pixels”. You can choose the color by clicking on the “Select Color…” button.

The “Select Directory...” button allows choosing the default save directory.

An option allows the save of a .txt file including the color modification information, e.g.:

All the settings are applied when you choose them and the “OK” button save them in a file named “transparency_settings.properties” for next time you will open the software. This file need to be on the same directory as the software to operate.

Save (pull down menu Save Modified Image or Ctrl-S): save the modified image in jpeg format. If the background is an image, the modified image is saved with the same dimensions. If a background color is selected, the image is saved with the dimensions chosen in the settings. In any case, the image is saved with the same settings (borders, invalid pixels) as displayed on the window.