5.5.  Sample Points Dialog

Revision History
Revision $Revision: 2474 $ 2008-03-01 ude

While the Color Picker can display color information about one pixel, the “Sample Points” dialog can display the data of four pixels of the active layer or the image, at the same time. Another important difference is that the values of these points are changed in real time as you are working on the image.

5.5.1.  Activate Dialog

The dialog “Sample points” is dockable. Read Section 2.3, “ Dialogs and Docking to learn more about the concept of dockability. You can access to this dialog in different ways:

  • From the toolbox-menu and the image Menu bar: FileDialogsSample Points

  • From the image Menu-bar: DialogsSample Points

5.5.2.  Using sample points

To create a sample point, Ctrl-click on one of the two measure rules of the image window and drag the mouse pointer. Two perpendicular guides appear. The sample point is where both guides intersect. You can see its coordinates in the lower left corner and the information bar of the image window. Release the mouse button.

By default, this sample point comes with a round mark and an order number. You can cancel these marks by unchecking the Show Sample Points option in the View menu.

The “Sample Points” dialog should automatically open when you create a sample point. This is not the case; you have to open it manually.

You can delete a sample point, as you do with guides, by click-and-dragging it up to a rule. Order numbers are automatically re-arranged in the dialog window; the most recent are moved one rank up.

By default, sampling is performed on all layers. If you want to sample on the active layer only, uncheck the Sample merged option in the tab menu:

Figure 14.73.  The “Sample Point” menu

The Sample Point menu

5.5.3.  Sample Points” dialog description

Figure 14.74.  Sample points dialog

Sample points dialog

The informations of four sample points are displayed in this window. You can create more, which will be existing and not shown. To show them, you have to delete displayed points.

The color of the sampled point is displayed in a swatch box.

In the drop-down list, you can choose between:


This choice displays the Red, Green, Blue and Alpha values of the pixel, as numbers between 0 and 255.


This choice displays the Red, Green, Blue and Alpha values of the pixel, as percentages. It also shows the hexadecimal value of the pixel's color.


This choice displays the Hue, in degrees, as well as the Saturation, Value and Alpha of the pixel, as percentages.


This choice displays the Cyan, Magenta, Yellow, Black and Alpha values of the pixel, as percentages.

Data are supplied for every channel in the chosen color model. The Alpha is present only if the image holds an Alpha channel.