## Review: Alpha Paint

### By: Douglas J. Nakakihara - djn@ix.netcom.com

NOTICE: This is the originally submitted text for an article that appeared in issue #138 of MICROTIMES magazine. (There are some slight edited differences between the published version and this one.)

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Copyright(C)1995 Douglas J. Nakakihara.

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Alpha Paint: 36-bit Butter for your Toast
By Douglas J. Nakakihara

If you really need professional results, I've always thought that it was better to paint in RGB and then hope and pray it looked OK on a composite monitor. Well, after using AlphaPaint from InnoVision Technology, I can now see that the problem was in my tools, not in the display capability. Alpha Paint lets you paint right on the Toaster's Program monitor, so it's WYSIWYG in the purest sense.

### Alpha Channel

With 24-bit real-time painting capabilities, an 8-bit graphics alpha channel, and a 4-bit dithered video alpha channel, Alpha Paint is billed as a "36-bit" paint program. Actually, Alpha Paint implements several different alpha channel tools. There are brush graphics and video alpha channels, a weight (density) control, and a stencil alpha channel.

Generally, graphics alpha channels are used to composite graphics together, like when you stamp a brush down with some level of transparency over a full-screen image. Video alpha channels allow video to show through graphics. So parts of an image may appe ar solid when viewed as a graphic; however, when keyed over video, defined areas will appear transparent, letting you see the underlying video.

The brush alpha channels affect the pen or brush you are painting with and allow you to independently control their graphics and video transparency. Weight control is a global density setting and directs the overall amount of "paint" that is applied. The stencil alpha channel is a protection mechanism that masks out defined areas of the screen.

The Magic Wand tool lets you quickly define a stencil alpha channel. Using a definable tolerance range, this tool will unprotect (unmask) areas of the screen. This works best when the desired object is against a fairly solid-color background. Depending on the situation, this feature may eliminate the need to trace an object by hand.

### Hyper-Palette

Alpha Paint's palette has 200 "Color Boxes" displayed in selectable banks of 20. In addition to merely defining a solid color, a Color Box can also define a "spread pattern" (see below). This allows you to quickly fill objects with gradients and other patterns as well as define alpha channels.

As you would expect, you can copy between Color Boxes, swap contents, and create a spread between two Boxes. Individual colors can be defined using either RGB or HSV (Hue, Saturation, and Value) values. There is also a 24-bit hue and saturation color wheel called a "Color Cube" and a Value slider available to visually fix a color.

### Spread 'Em

The right side of the Palette menu is devoted to custom "spreads." Essentially this is a color range creation tool, but goes beyond the usual implementation. As you add colors to the "Spread Preview Bar", a gradient is formed based on where you place the colors on the bar. A color can be repositioned by simply dragging its position indicator, and there is an option to evenly space all colors. Color order can be globally rotated or inverted. Individual colors can be deleted or duplicated as well. Spreads can be linear, circular, or radial. Plus, you can adjust the Z-axis rotation of linear and radial spreads.

### Drawing Tools

The basic drawing tools like line, curve, rectangle, circle, ellipse, polygon, free-hand shape, fill, text, airbrush, etc. are present and accounted for. The cutting tool is used in conjunction with any of the geometric shape drawing tools (i.e., circle, polygon, etc.). Magnification is fixed at 75, 100, 200, 400, and 800 percent of normal.

In the Pen menu, you can choose between circle, oval, and rectangle for your pen shape. Besides just allowing you to adjust the pen size, you can also adjust its width and even rotate it. (Obviously, the later doesn't do much if your pen shape is a circle .) Adjustable feathering is available to give brush strokes a soft professional-looking edge. The Fade setting allows you to define how the applied pen or brush will gradually increase or decrease in one continuous stroke.

### Fill 'Er Up

The common Fill tool has some interesting nuances in Alpha Paint. Not only can you fill an area with a brush, but you have the option of automatically scaling it to fit the area or having it warped to fill the area. A tolerance level can be set to determine how close to the original color a pixel can be when Alpha Paint calculates the fill area.

### Text

Alpha Paint supports Toaster, Chroma, and Postscript fonts. Adjustable attributes include height, width, italics, character spacing, Z-axis rotation, line spacing, and line justification. With Postscript fonts, you have the option of wrapping the text around a circle. Once the text has been defined, you can then apply brush attributes, like rotation, shadows, etc.

### Brushing Up

Brushes can be loaded (and saved) from the Brush menu in addition to being cut-out from the main screen. When loading a brush you have the options of trimming black pixels (RGB 0,0,0) from the edges and adjusting the aspect ratio for (square pixel) brushes created on the Macintosh. From this menu you also set the global brush graphics and video alpha channels.

You may also size and rotate a brush. The parameters for both of these attributes may be set manually or interactively. When rotating a brush, besides allowing you to position and rotate in the X, Y, and Z dimensions, you can also set the focal length. This allows you to set the visual depth of field making the brush appear flat or elongated along the Z-axis.

Brushes can be given a beveled edge, outlined, and extruded. There are also provisions for shadows, as well as back-lit glow and neon-outline effects, all with adjustable parameters. As an alternative to a brush's original colors, you can change them to any of the Color Boxes or even map a new image on it. Edges have the option of being feathered. You may set independent graphics and video visibility parameters, which are used in conjunction with the brush alpha channel settings. Most of these brush attributes are equally applicable to when you are drawing with a pen or adding text.

The brush tools are also used for compositing full-screen images using alpha channels. For example, by selecting a left-to-right greyscale-gradient Color Box for the graphics alpha channel, a full-screen brush can be stamped down and fade in horizontally over a colored background.

### Drawing Modes

In addition to a normal drawing mode there is Rub Thru, Erase, Hue, Colorize, Negative, Smear, Watercolor, Mix, Lighten, Darken, Smooth, Sharpen, Gamma, Contrast, and Oil Paint. Rub Thru lets you paint the swap screen image into the main screen. The Erase mode replaces pixels with the current background color. Hue replaces the color hue of a pixel with the that of the current Color Box. Colorize replaces the hue and saturation and can be used to colorize greyscale images. The Negative mode reverses the RGB value of pixels.

The Smear mode smudges areas of an image. Watercolor paints with the current Color Box, but blends-in existing pixels. Mix is similar but uses an existing color in the image instead of the Color Box. Smooth can be used to blur the edges of an object while Sharpen enhances edges. Gamma and Contrast adjust the difference between light and dark colors. The Oil Paint mode applies an "impressionist painting style" that mimics oil painting.

To make using things like Rub Thru a little easier, there is an "Onion Skin" option. This allows the swap screen to show thru at 25-percent visibility.

### TV O.D.'d

The TV Controls Menu includes standard image correction parameters like gamma, contrast, brightness, color, sharpness, tint, red, green, and blue. Additionally, there are special effect operators like embossing, negative, posterize, mosaic, and oil paint. Embossing adds an engraved look to an image. Posterize reduces the number of colors yielding a "blown-up" poster-like effect. Mosaic pixelizes the picture into squares. Negative and Oil Paint work as described previously for Drawing modes.

### I Do I Don't

If you're like me and love to try many things out before committing (OK, some people call these mistakes.), you'll be glad to know that Alpha Paint features multiple undo and redo, limited only by your RAM. Moreover, redo is taken one step further with Redo+. This will re-perform the last drawing operation using the existing paint attributes. So let's say you just painstakingly outlined an object by hand, but you forgot you wanted a feathered border. Well just undo your first attempt, adjust the feathering setting, and hit Redo+. This can save you so much time when you're trying to tweak something to get "just" the right effect.

Where appropriate, Alpha Paint features preview windows that give you a rough idea of what the results of your settings will be. Definitely a time-saver and something we're seeing more and more of in newer applications.

### File Formats

Alpha Paint can save images in Framestore, IFF24, and JPEG formats. Brushes can be saved in IFF24 only. Alpha Paint can load these formats, plus rendered Toaster/Montage CG pages and all IFF images, except low-res HAM6. (Note: Montage is InnoVision's Toaster CG product.)

### Graphics on Video

The Play Menu combines some basic functions of the Toaster Switcher and Alpha Paint graphics. Generally this will be used to overlay graphics on video; however, you can also overlay video on video with an alpha channel mask. For transitions, a fixed-speed fade and cut are provided.

### Little Big Things

There are so many little things in Alpha Paint designed to save time and make your life easier. For example, if you want a brush automatically pasted down in the center of the screen, just press the Return key. The Clear-to tool lets you quickly clear the screen to any color/pattern in the palette. Often after you've adjusted a bunch of settings for a certain effect, you may want to clear out all settings and start fresh for the next one. Just hit the F1 key and everything is reset to the default settings, but the image is left untouched.

### System Requirements

Alpha Paint requires Video Toaster 2.0 or greater, 12MB Fast RAM, 1MB Chip RAM, 10MB hard drive space, a 68030 CPU or better, and AmigaDOS 1.3+. Alpha Paint does some serious calculations and you'll want all of the horsepower you can get! The program also supports Wacom and CalComp pressure sensitive drawing tablets.

### Comments and Criticisms

Alpha Paint really needs ARexx support. Besides just being able to batch process images, it would allow you to animate some of the effects. It would also be nice if all option parameters could be set using the mouse, instead of only some. This would minimize having to move your hand back and forth between the mouse and keyboard. The mini-sliders introduced in LightWave 3.5 would be perfect.

Another limitation is that you cannot multitask out of Alpha Paint and do something else. It basically takes over the whole machine. (I am told, however, that this was a necessary evil to get Alpha Paint to perform its magic.)

I also wish that the controls interface optionally or simultaneously appeared on the Amiga RGB monitor. Some Toaster users (like me) have their Toaster monitors off to the side. As such, they may not be located in a position where it is comfortable to do detailed work. Interestingly, you can faintly see the interface on the Amiga RGB monitor if you turn the brightness up on your monitor.

### Conclusion

Alpha Paint is one heck of a program. It comes with a thick three-ring notebook manual with many tutorials to have you up and running in no time. You'll soon be able to literally whip up a beautiful complex video graphic in just minutes.

I'll be the first to admit that you could duplicate everything that Alpha Paint does using other programs you probably already have. However, Alpha Paint puts it all there right in front of you. Right at your finger tips. All wrapped up in one straight-forward easy-to-use package. If you make your living with the Toaster, you need this program. It's priced a bit higher than other Amiga paint programs, but it will save you time and quickly pay for itself.

AlphaPaint
$699.95 (Available direct for $399 for a limited time)
InnoVision Technology
1933 Davis Street, Ste 238
San Leandro, CA 94577
(510) 638-0800