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Configuring N-Paint

This chapter describes how to use N-Paint's Setup mode to define certain N-Paint parameters.

In this Chapter

In this chapter, we'll describe how to use the N-Paint Setup menus to configure N-Paint.

The Setup Menu

The Setup menu lets you define several parameters which affect the "look and feel" of N-Paint. While the default settings for N-Paint are those that most users are comfortable with, you may want to customize them. You can modify N-Paint Setup parameters at any time, the changes you make take effect immediately.

Setup Parameters

To view the Setup parameters, (CLICK-L) on the Setup menu item. The following menu appears:

Figure 2.1 Setup parameters

Save Unpaint

Specifies whether to save unpaint on all painting and drawing operations. If this feature is turned off, you may see a slight performance improvement. You can also turn off the unpaint feature if you are low on memory.

Confirm Enabled

If Confirm Enabled is on, a confirmation menu will appear whenever you perform a potentially destructive operation (such as erasing the entire canvas).

Use I/O LUT

Enable Input/Output Look-Up Table. You can use the Look-Up table to determine how color values are mapped between different color depths. N-Paint has a 16-bit architecture, which means that each pixel has 4 components (RGBA), each of 16 bits, for a total of 64. When you load or save image which have different color depths, like an 8-bit image, color values must be mapped between the two color depths.

Table 2.1 Mapping between 8 and 16 bits

Status Depth Before (binary) After (binary) Before (decimal) After (decimal)
Off

8 ` 16

11111111

1111111100000000

255

65280

On

8 ` 16

11111111

1111111111111111

255

65535

Off

16 ` 8

11111110 11111111

11111110

65279

254

On

16 ` 8

11111110 11111111

11111111

65279

255

The first line in Table 2.1 shows what would happen to a pixel of pure white if loaded with Use I/O LUT off-the 8 bits of data are loaded into the most significant bits of the 16-bit channel and the least significant bits are padded with zeroes.

The second line shows what happens to that same pixel with Use I/O LUT on. N-Paint uses a lookup table to determine the appropriate 16-bit value for the 8-bit value.

The third line shows what happens when saving a 16-bit channel into an 8-bit channel with Use I/O LUT off-the 8 least significant bits are truncated.

The fourth line shows what happens when saving a 16-bit channel into an 8-bit channel with Use I/O LUT on-the 16-bit value is rounded to the nearest 8-bit value after division by 256.

There is a trade-off; turning Use I/O LUT on ensures color consistency when loading 8-bit images, but is slightly slower. Turning Use I/O LUT off introduces a minor amount of data noise but is faster.

Typically, you might do your setup work with the feature turned off, then turn it on when you are ready to actually write out modified images.

Note that this effect becomes particularly visible in cases where you are switching between 8 and 16 bits in any repetitive sequence; turning Use I/O LUT off can cause a buildup of degradation with each subsequent save of the image.

Debugger Enabled

When the Debugger is enabled, an additional option is displayed on any error dialog box, allowing you to enter the LISP debugger.

Use Mouse Buttons

Determines how the mouse interacts with N-Paint:

If selected, N-Paint operations are determined by which mouse button is selected; that is, the middle and right buttons have different functions than the left button.

If not selected, all three mouse buttons are identical, and are modified using the CTRL and ALT keys. If you are using a tablet, this should not be selected. For more information, see the section "Using the Tablet and Mouse" in "About this Document."

Horiz Stretch

Controls the horizontal stretch factor to be used for displays with non-square pixels. This is automatically set when the canvas is created. You can override the specified stretch factor and specify whether or not stretch factor is used.

Numeric Keypad

When this feature is enabled, a numeric keypad appears when you (CLICK-L/M/R) on a number edit box.

Figure 2.2 A numeric keypad

Otherwise, you edit numeric values like this:

(CLICK-L) to position the cursor in the numeric edit box.
(CLICK-M) or (CLICK-R) to clear the numeric edit box.

: Note. If you want to enter numbers using the numeric keypad on the keyboard, make sure that the keypad option is turned off and press the Num Lock key on the keyboard.

Unpaint Parameters

The unpaint parameters define how N-Paint's undo feature works; (CLICK-L) on the Unpaint Parameters button to display the following menu:

Figure 2.3 Unpaint parameters

Unpaint Delay specifies the delay before the unpaint starts when you (CLICK-L) on the Undo button.

Unpaint Size determines how many pixels are stored in the unpaint buffer. This determines how many operations can be "undone". A higher value means more operations can be undone, but also consumes more memory.

Unpaint Index Size is the size of the index that keeps track of the operations to be undone. While the default (32767) may seem high, it is certainly possible to use more memory than this when working with multiple images, or if you need to undo many operations.

Startup Options

Startup options define how N-Paint configures itself on startup. (CLICK-L) on the Startup Options button to display the following menu:

Figure 2.4 Startup options

Initial Canvas Color sets the color for the painting canvas when starting N-Paint.

Tablet Enabled specifies whether or not a tablet is attached to the workstation.

Initial Image File specifies a default image loaded when N-Paint is started.

Horiz Stretch

Specifies the amount by which individual pixels are "stretched" (if horizontal stretch is enabled by pressing the Horiz Stretch button).

Fast Warp Size

Specifies the quality for any operations using the warp ink. A lower value produces images "truer" to the original, while higher values produce "chunkier" results.

Color Warning

If selected, a warning message is displayed if you select an invalid color for one of the following color-spaces:

NTSC

PAL

601

Menu Mode

Specifies the level of menu complexity:

Short mode is useful when first learning the system-only a basic set of menu items is displayed.

Normal is a good working mode; most elements in the menus are displayed, except for several advanced features.

Long mode displays full menus.

Derez Width

Specifies the width of the canvas when displayed in de-rez mode (used, for example, to pull a matte using a lower resolution version of the currently displayed canvas).

Target Platform

Specifies the gain and gamma values to be used for the N-Paint display. (CLICK-L) on this field to reveal a pop-up menu, listing your choices:

Figure 2.5 Select target platform pop-up

(CLICK-L) on a platform to select it. Table 2.2 shows the default gamma and gain values for each platform.

Revert resets target platform parameters to their default values, undoing any changes to these parameters you may have made.

Create New allows you to create a new target platform specification. See below for an explanation of the Target Platform parameters.

Edit allows you to change the gamma and gain values for the currently selected target platform. (CLICK-L) on Edit to reveal the Platform Settings dialog:

Figure 2.6 Platform Settings dialog

Name is the name of the platform as it appears in the Select Target Platform pop-up menu (Figure 2.5).
Full Name is a longer description of the target platform. Full Name is only visible in this dialog.
Gamma (RGB) consists of three fields, one for each of the Red, Green, and Blue components of an RGB image. To change a setting, (CLICK-L) in the field and enter a new value.

Gain (RGB) consists of three fields, one for each of the Red, Green, and Blue components of an RGB image. To change a setting, (CLICK-L) in the field and enter a new value.

Table 2.2 Default gamma and gain settings for Target Platforms

Platform Gamma (RGB) Gain (RGB)
PC

1.0 1.0 1.0

1.0 1.0 1.0

N-64

1.0 1.0 1.0

1.0 1.0 1.0

Saturn

1.0 1.0 1.0

1.0 1.0 1.0

SGI

1.7 1.7 1.7

1.0 1.0 1.0

Playstation

1.0 1.0 1.0

1.0 1.0 1.0

Color Reduction Parameters

These parameters which affect the behavior of the N-Paints Color Reduction module.

Auto Highlight

When you click on a slot in the palette in Color Reduction, pixels in the image which map to that slot are automatically highlighted when Auto Highlight is on.

Auto Remap

When toggled on, images are automatically remapped to the current palette. Otherwise, you must remap the images manually.

If Auto Remap is selected, then image indices will be automatically reordered following any operation which moves slots in the palette.

Dither Method

Specifies a method for dithering colors in color-reduced images. (CLICK-L) on the Dither Method field for a pop-up menu listing possible methods for dithering.

Error Propagation - uses the Floyd-Steinberg algorithm.

VRAM Editor Parameters

Stop at failure?

When this option is selected, the VRAM Editor will return an error message when it is unable to place a tile using the Best Fit algorithm. Otherwise, the offending tile will not be placed, but no error message will appear.

Use DOS filename?

When this option is toggled, TIM file names are truncated to eight characters in accordance with DOS file name requirements. For example, CharacterSprite.lbm will end up as Characte.TIM.

Additional Setup Parameters

At the far right of the screen, an additional area controls the display channels and the current memory and disk usage:

Figure 2.7 N-Paint memory usage

Display Channels

The Display Channels section allows you to specify which channels of an image are displayed. Note that this does not affect which channels of an image are modified by a particular operation.

RGB - Display all non-alpha channels of an image (You can turn the matte on and off manually in the N-Paint menus).

Red - Displays only the red channel of an image.

Green - Displays only the green channel of an image.

Blue - Displays only the blue channel of an image.

Tablet

The Tablet section appears in the Setup menu only if a tablet is hooked up to the machine on which N-Paint is installed:

Reset Tablet issues a reset command to the tablet.

Pressure Min specifies the minimum amount of pressure required for painting to occur. The range is 0 to 255.

Pressure Exp is an exponent which controls how a change in tablet pressure maps to a change in brush opacity.

Color Bars

The color bars option lets you generate a canvas of standard color bars. (CLICK-L) on the Color Bars button to select which option you want:

Figure 2.8 Color bars

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