When you work with a physical surface (like paper or canvas), you can only paint or paste over the existing layers. VizPaint2D's composition modes let you add new layers in eleven different ways:
By understanding the composition modes, you will be able to exercise the capabilities of VizPaint2D and achieve extraordinary effects.
Tip: Once you have integrated a layer with the layer on the canvas, you cannot remove just a single layer. |
When you create masks, the only composition modes available are over, erase, and replace.
Over mode applies any color, text, or picture directly on top of whatever already exists on the canvas. Combining the over mode with a 100% opacity setting completely covers the painted area. Using over mode with a lower opacity setting allows some of the existing layer to show through. (See figure 4.)
Under mode applies changes behind the existing layers. For changes made in under mode to be visible, part of the canvas needs to be either blank or filled with areas of low opacity. If your canvas is a completely opaque picture, you will not see anything painted using under mode.
Atop mode applies changes only over painted areas, not on blank portions of the canvas. (Painted areas are defined as those with partially or fully opaque alpha values.)
For example, if you were brushing pink strokes on a canvas that contained only a green rectangle, the pink would show only on the area covered by the rectangle.
Figure 4 Composition modes-over, under, atop, erase
Erase mode removes any existing color and alpha, text, or image. Erasing an area with a low opacity clears it gradually. By setting the opacity to 100%, you can completely erase an area with a single stroke.
Erasing with a picture that includes different opacity levels results in both partially and completely cleared areas of the canvas
Replace mode substitutes new changes for any existing color, text, or images. With replace mode, the entire area is wiped clean before the new layer is applied so that nothing exists underneath it. If you are pasting a picture in this mode, any transparent areas of the image or cutout will be blank.
Replace mode is only effective with VizPaint2D's paste-up, flip, grade, and reflect tools. With the brush tool, replace mode produces the same effect as over mode.
The fore and background modes are similar to the over and under modes described previously. Use these two modes when you want to achieve a "layered effect" within a single canvas.
The difference between these modes and the over and under modes lies in the way that the alpha channel is handled.
Tip: We do not recommend using the fore and behind composition modes with the brush tools. |
Use fore (for "foreground") mode to apply color, text, or pictures in front of the existing layers.
Use behind mode to apply color, text, or pictures behind the existing layers.
The hue, saturation, value, and watercolor modes have no effect on a blank canvas. Use these modes only to change areas with existing color, text, or images.
Hue mode changes the hue or pure color of an existing layer. When working in hue mode, the color of the area changes to the chosen color. Any shadows or highlights remain intact.
When working in hue mode, it may help to use the HSV slider palette to see the selected hue.
Hue mode has no effect on the existing level of brightness or "saturation." Using hue mode on an area with very desaturated color has minimal effect. So if you are working on a black and white picture, you cannot add color to it with hue mode.
Hue mode has little effect on very dark areas, because it does not affect the "value" component which makes things look dark.
Saturation mode changes the saturation or intensity of an existing layer. A completely saturated color contains no white, only pure hue; a desaturated color is almost totally white with no hue. The saturation mode would not change yellow to green, but it could make the yellow either more intense or paler.
When working in saturation mode, it is helpful to use the HSV slider palette to see the saturation level of the selected color. Using a very desaturated color in this mode changes a colored area to black and white.
Value mode changes only the value level or amount of black in an existing layer. Working in value mode affects only the shadows or highlights of the area. The hue and saturation remain the same.
When working in value mode, it is helpful to use the HSV slider palette to see the value level of the selected color. If the color is very light, value mode wipes out shadows. If the color is dark, highlights are eliminated.
By using value mode at low opacity levels, you can make subtle changes to the shadows and highlights in a picture. If you use value mode to paste one picture onto another, the resulting effect shows the shadows and highlights of the new layer on the color of the existing layer.
Watercolor mode changes two components of the existing layer: hue and saturation. With watercolor mode, only the highlights and shadows of the existing layer are maintained.
When working in watercolor mode, it is helpful to use the HSV slider palette to see both the hue and saturation level of the selected color. Unlike hue mode, you can use watercolor mode to add color to a black and white picture.