Vector Masks

A vector mask creates a transparency effect based on a style of gradient ink, such as radial or rectangular. You can choose the style when you apply a vector mask, or you can apply an existing vector object as a vector mask.

A vector mask can be applied to any type of objects, including vector, paint, text, and group objects.

It’s easy to apply vector masks. You can drag a vector transparency tool to apply radial, directional, elliptical, or rectangular style masks. You can apply a mask quickly by selecting an object and choosing Object | SpriteLayers and selecting a vector mask style in the submenu.

The styles of vector masks applied by the Vector Transparency tools are related to vector gradient styles. You can think of these tools as applying a hidden gradient to a masked object. The transparency effect is based on the hidden gradient; the transparency level is relative to the lightness of the gradient shading.

For example, a linear vector gradient blends colors along a straight axis. A directional vector mask fades from opaque to transparent along a linear axis. For linear vector gradients and directional vector masks, you can specify the length and angle of the axis.

The relationship between vector gradients and vector transparency masks can be seen if you detach a vector transparency mask. With a masked object selected, choose Object | SpriteLayers | Detach Mask. Canvas X Draw removes the vector mask and places it in the document as a separate vector object. If you examine this object, you see that it has a vector gradient. The gradient style is similar to the vector mask style. The vector gradient fades from black to white in the same way that the vector mask caused the masked object to fade from transparent to opaque.

The relationship between vector masks and vector gradients also works in reverse; use a vector gradient-filled object as a vector mask. (See Masking with a Vector Object.)

A vector mask is related to a vector gradient. If you detach a vector mask, you get an object with a gradient. The grays in the gradient correspond to transparency levels in a masked object.

Applying Vector Masks

You can apply a vector mask using the Vector Transparency tools. When an object is selected, you can drag one of these tools near or over the object to apply a transparency effect.

The Vector Transparency tools provide the easiest way to create transparency effects, such as vignettes, (images that appear in ovals and other shapes), as well as linear, radial, or rectangular fades.

To Create a Vector Mask:

1. Select a text, paint, vector, or group object to mask.
2. Select a Vector Transparency tool. Select the tool for the style of vector mask you want to apply: Radial, Directional, Rectangular, or Elliptical.



3. Drag the tool near or over the selected object.

As you drag, a vector line or shape appears, which represents the position of the vector transparency effect.

4. To adjust the effect, drag a handle to reposition the transparency vector.
5. Press Esc to leave Edit mode.

To Set the Vector Mask Scope:

When you apply a vector mask to a vector object, the mask affects the vector object’s fill ink or its fill ink and stroke (pen ink). To change the effect, change the Scope option in the Properties bar. (See Controlling the Scope of Transparency Effects.)

Masking with a Vector Object

Create a vector mask by attaching a vector object to another object. Like other vector masks, a vector mask created from a vector object produces transparency relative to its color values; e.g., if the vector object that you attach is solid white, it creates no transparency; if it is solid black, it creates 100% transparency, making the masked object invisible.

To Attach a Vector Mask:

1. Place a vector object to use as a mask in front of the object to be masked. The two objects do not have to overlap or touch, but the vector object must be in front of the other object in the stacking order.
2. Select both objects.
3. Choose Object | SpriteLayers | Attach Mask. Canvas X Draw creates a vector mask and both objects remain selected. The original vector object is not changed.

If the vector object and the object to be masked aren’t the same size, Canvas X Draw scales the vector object to fit the masked object.

Editing Vector Masks

You can edit vector masks that have been applied with the Vector Transparency tools, and masks created by attaching gradient-filled vector objects. Editing lets you change the boundary of the opaque and transparent areas of a mask. You can also add nodes for finer control of transparency levels.

To Edit a Vector Mask:

1. Select the Vector Transparency tool that was used to apply the mask from the Toolbox.
2. Select the object with the vector transparency mask you would like to edit.
3. Drag the vector mask editing handles to adjust the position and boundaries of the vector mask.
4. Press Esc when you finish editing.

Adding Nodes

The default handles that appear in Vector Mask Edit mode indicate the start and end points of the transparency gradient. For a directional mask (the most basic style), a hollow handle represents the point of 100% transparency, and the solid handle represents the point of 100% opacity.

When a vector mask is in Edit mode, you can add nodes to set additional opacity levels. The default mask has a start and end point, with a smooth transition from opacity to transparency between the start and end point. When you add nodes, set the opacity level at each node.

To Add a Node:

1. Select the masked object and then click the Vector Transparency tool for the mask style to enter Edit mode.
2. Point to the vector mask and right-click. An opacity slider appears.
3. Use the slider to set the opacity level of the new node; i.e., 100 makes the mask opaque at the node, whereas 0 makes the mask completely transparent at the node.
4. Select a value between 0 and 100 to make the mask semi-transparent at the node.

Use the pop-up opacity slider to set the opacity level of a node. You can add a series of nodes for additional control of a transparency mask.

When you edit rectangular or elliptical vector mask styles, add nodes to the horizontal vector that joins the inner box, (which represents the area of 100% opacity), to the object’s bounding box. When you edit radial mask styles, you can add nodes to the circle, which represents the 360° sweep of the mask.

Removing a Vector Mask

Removing a vector mask from an object removes the transparency effect produced by the mask.

1. Select the masked object.
2. Choose Object | SpriteLayers | Detach Mask. Canvas X Draw removes the vector mask from the selected object.

When you detach a vector mask, the former mask appears in the document as a separate vector object filled with a grayscale gradient.

Vector Masks in Paint Edit Mode

If a paint object has a vector mask, Canvas X Draw temporarily represents the vector mask as a channel mask if you edit the paint object.

In Paint Edit mode, a temporary channel mask that represents the object’s vector mask appears in the Channel Mask slot in the Channels palette. The temporary mask lets you see the effect of the vector mask as you edit the paint object.

If you click in the Channel Mask slot to try to select the temporary channel mask for editing, Canvas X Draw asks if you want to convert the vector mask to a channel mask.

• Click Cancel to return to editing the paint object without destroying the vector mask.
• Click Yes if you want Canvas X Draw to convert the vector mask to a channel mask that can be edited with painting tools. (See Editing Channel Masks.)

Using Transfer Modes

All objects—vector objects, text objects, paint objects, and group objects—have transfer modes, which are like invisible filters that affect the appearance of colors. When objects overlap, the transfer mode of the front object can change the appearance of the back object.

Transfer modes work with transparency effects, including opacity and transparency masks; however, transfer modes can make objects appear to be transparent without reduced opacity or transparency masks; e.g., Multiply mode lets underlying colors show through an object. The default transfer mode is Normal; i.e., the colors of overlapping objects do not mix unless the front object is partially transparent.

In addition to interacting with background objects, transfer modes can interact with the document’s white background. When an object’s transfer mode is Screen, anything white replaces the object’s color, so the document’s white background can make the object seem to be invisible.

For vector objects, apply transfer modes to fill inks alone or to fill inks and strokes together.

To Change an Object’s Transfer Mode:

1. Select an object and choose a mode in the Transfer Mode menu in the Properties bar.
2. For vector objects, select a Scope option for either the Fill or Fill & Stroke.

Available Transfer Modes

The following descriptions are based on objects with RGB colors with no other transparency effects. Each mode is described in terms of the front object when the back object’s transfer mode is Normal.

• Normal: Colors do not blend; the color of a front object hides the colors of all objects behind it.
• Multiply: Overlapping colors become darker. Black produces black. White has no effect, the same as if a white object were not visible. White text, for example, reveals the background.
• Screen: Overlapping colors are lightened. Objects with lighter colors increase the effect. White produces white. Black has no effect, the same as if a black object were not visible. Black text, for example, reveals the background.
• Overlay: A front object’s color overlays colors in the background, while preserving highlights and shadows. White and black in the background are not affected.
• Soft Light: Underlying colors are lightened or darkened depending on the brightness of the front color. Colors in front that are lighter than 50% gray lighten the underlying object. Colors in front that are darker than 50% gray darken the underlying object.
• Hard Light: Underlying colors are lightened or darkened depending on the brightness value of the front color. Hard Light mode is similar to Soft Light. However, black in the front object produces black; white in the front object produces white.
• Darken: The color values of the front color replace the underlying color values if the front color value is darker than the back color value. Black in the background appears unchanged; the front color appears in place of white in the background.
• Lighten: The color values of the front color replace the underlying color values if the front color value is lighter than the back color value. White in the background appears unchanged; the front color appears in place of black in the background.
• Difference: The color value of the front and back colors are compared and the darker value is subtracted from the lighter value. If the front and back colors are identical, the result is black. If the front or back color is black, the other color does not change. If the front or back color is white, the other color is inverted.
• Dodge: Dodge mode compares the lightness values in each channel of the front and back colors, and uses the lighter value from each channel for the result color. However, black is not replaced by a lighter color. White in the front replaces all colors except black.
• Burn: Burn mode compares the lightness values in each channel of the front and back colors, and uses the darker value from each channel for the result color. However, white is not replaced by a darker color. Black in front replaces all colors except white.r

Color Modes

Canvas X Draw calculates transfer mode effects by applying formulas to color values. Canvas X Draw performs these calculations using RGB color values or CMYK color values.

For example, the formula for Multiply mode is Color 1 multiplied by Color 2. Canvas X Draw applies the formula separately to each value that defines a color. In the case of RGB colors, Canvas X Draw applies the formula separately to the red, green, and blue values. For CMYK colors, Canvas X Draw calculates the effect on cyan, magenta, yellow, and black values.

The significance of the color space calculation is that the effect you see on screen could appear completely different if the effect is printed in a different color space.

In particular, you must display transfer mode effects in CMYK if the document will be separated for printing with process (CMYK) colors. Otherwise, the color separations could produce colors that are completely different from the colors you see on screen.

For an example of this effect, draw several overlapping objects with different colors. Set the transfer mode of the front object to Difference. (See Available Transfer Modes.) Choose Layout | Display Options. In the Display Options manager, change the Mode from RGB to CMYK. Click OK to close the manager. To refresh the screen, press Command + R. You will probably see a significant change in colors when you switch from RGB to CMYK mode.

Select Grayscale from the menu to lessen the required memory if working on complex graphics or editing images. In Grayscale mode, your screen redraws faster than in CMYK or RGB.

To Set the Color Mode for Screen Compositing:

1. Choose Layout | Display Options.
2. Select Grayscale, RGB, or CMYK in the Mode menu in the Display Options manager. Choose RGB for effects that will be displayed in RGB colors. Choose CMYK if you are using CMYK colors in a document that will be printed with process colors.

See Also:

• Controlling the Scope of Transparency Effects
• Channel Masks