View - Panes - Layers

The Layers pane is used with mostly with map windows to control the stack of drawings, images and text components that appear in a map. It is also used with other components, for example, when an image window or drawing window or a layout window has the focus:


·      With an image window, the layers pane shows the border, background and image channels so that any of these items may be turned on or off.

·      With a drawing window, the layers pane shows the background and also any views of that drawing used in layouts.

·      With a print layout window, the layers pane shows individual elements in the layout to enable them to be turned on and off.


Using the Layers Pane with a Map Window


The layers pane displays the layer stack in a map. The layers pane is more convenient to use with many layers than the tab controls at the bottom of the map. For intensive image editing work involving many layers it provides faster control over layer characteristics (such as transparency) as well.


Layers Pane Controls


·      Click on a layer to highlight it and to make it the active layer.

·      Use the checkboxes to turn layers on and off for display.

·      Each image layer may be set to a percent opacity to specify partial layer opacity.

·      Move layers up and down in the layer stack with the Move Up and Move Down buttons.

·      The Border and Background may be turned off and on using their checkboxes.



Switch To - Make the highlighted layer the active layer in the map. Double clicking on a layer also will make it the active layer.


Show All - Show all layers in the map.


Hide All - Do not show any layers in the map.


Move to Top - Move the active layer to the top of the layer stack.


Move Up - Move the active layer up one position in the layer stack.


Move Down - Move the active layer down one position in the layer stack.


Move to Bottom - Move the active layer to the bottom of the layer stack.


Delete Layer - Remove this layer from the map.


Restrictions - Show and edit layer restrictions for the highlighted layer.


Opacity - Show opacity controls for layers.


Properties - Show properties for this component. Equivalent to opening the component in its own window and choosing View - Properties .


The Border and Background Layers


The layers pane will always show two additional layers: the Border layer and the Background layer. These are system layers and are not real "layers" in that they do not correspond to any drawing or image in the project. Both may be switched ON or OFF via their checkboxes.


The Background shows what color to put underneath all other layers. By default white, it may be switched off to easily see if any white space in the map is part of the background or not.


The Border shows the proposed size of the image for printing to a printer or to a file. It may also be used as a guide when merging images into each other. The Border can be shown in various styles, either as a simple border, as a border with all external areas opaque (to get a better idea of how an image cropped down to the frame size will look), or as a partially transparent matte in regions outside the frame. This latter setting gives an idea of what the final cropped image will look like while still allowing a view of items outside the frame to use as a guide when moving layers about to bring items into view.


Setting Background Color


Background color for all components is set by default in the Tools - Options dialog. Each individual component can have its background color set by opening the component in a window and choosing View - Properties.


Layer Restrictions


images\btn_layer_restrict.gif The Restrictions button in the layers pane displays and sets layer restrictions. Layer restrictions may also be set by right clicking on a layer tab in a map window and choosing Restrictions.


Each layer within a map may be specified to be clickable, editable or selectable (in any combination) with mouse commands. Each layer has three restriction options:


·      Enable mouse clicks

·      Enable mouse editing

·      Enable mouse selection


By default, all three options are enabled so objects in layers by default may be clicked, edited or selected.




The layers pane shows edit restrictions with a no marking each restriction. The "yes" implied by default is not shown for greater legibility. For example, in the above illustration the Cities layer is clickable but not editable or selectable. Double-click into any restriction setting in the layers pane to toggle it between no and the default yes setting.




If we were to right click on the Cities layer tab in the map and choose Restrictions the Layer Restrictions dialog would show restrictions status for that layer. In this dialog a check mark enables the function and no check mark removes the function. For example unchecking the Enable mouse edits box will prevent a CTRL-ALT click on an object in that layer from selecting it for editing.


Layer restrictions are used to show layers in maps while preventing some layers from participating in mouse commands. This makes it easier to edit desired layers in complex maps. Another use for layer restrictions is in Manifold IMS to restrict the action of hyperlinks or the Info tool to a limited set of layers.


Layer restrictions operate only with mouse commands. Keyboard and menu commands are not limited by layer restrictions. For example, if a layer has had the Enable mouse selection checkbox unchecked none of the mouse selection commands will select objects in that layer. However, using CTRL-A or Edit - Select All will select all objects in that layer, the query toolbar will select objects in that layer and queries will select objects in that layer.


Layer Opacity


Image layers may be given an opacity percentage that applies to the entire layer. Zero percent is no opacity (totally transparent) while one hundred percent opacity makes the layer totally opaque. If an image layer contains an RGBa image where individual pixels may have different degrees of transparency, the layer opacity will be evenly combined in a proportional way with all pixels.


images\btn_layer_trans.gif To set layer opacity, press in the Opacity button and an Opacity column will appear in the layers pane. Double-click into the opacity value for each layer to change it. Enter a value from 0 to 100 (no need to enter the % character) and press Enter.


Using the Layers Pane with Drawings


The Layers pane is used to control the appearance of drawings within drawing windows. The layers pane includes checkboxes for the background and border. The border "layer" with drawings shows an enclosing box about the widest extents of objects in the drawing.



By default, drawings are shown using the checkerboard background Manifold uses to provide a backdrop for any transparent regions. The layers pane is shown to the right of the drawing window.



Checking the Background box in the layers pane will replace the checkerboard background with whatever is the default background color.



Checking the Borders box will draw a one-pixel border that represents the minimum enclosing box for all objects in the drawing. When working with drawings that include points, using the Border is a handy way to see if any very small objects exist far away and unnoticed from other objects, since the border will expand to include all objects.


The Layers pane will also show views of the drawing used in print layouts. See the Specifying Views in Layouts topic for details.


Using the Layers Pane with Images


The Layers pane shows all of the channels in the active image. The appearance of pixels comes from blending primary colors called channels. Channels and their use via the Layers pane are described in detail in the Images and Channels topic.



RGB images consist of three channels: red, green and blue.


By checking or unchecking the channel boxes we can turn each channels ON or OFF for display. For example, checking only the channel for blue and unchecking red and green channels will display a standard RGB image using only the blue tones of which it consists.



RGBa images have an additional channel called the Alpha channel that specifies transparency for each pixel.




If we have an RGBa image like the one above,



We can uncheck the Alpha channel.




Doing so removes the influence of the alpha transparency channel and so displays the image as an ordinary RGB image without per-pixel alpha transparency applied.


Compressed images will show R, G and B layers in the layers pane. If channel data from a multi-spectral image has been assigned to the alpha channel for a compressed image using the View - Display Options pane, then an alpha channel layer will appear in the layers pane as well for a compressed image.


See the Images topic and the Images and Channels topic for additional examples using the checkboxes.


Grayscale and Palette Images


Both grayscale and palette images have one channel:




A grayscale image is simply a palette image with a grayscale palette. For both grayscale and palette images the single palette channel will be shown in the Layers pane for these image types.


Border and Background


The border and background "layers" appear in the layers pane for images. These checkboxes control the appearance of a border frame around the image as well as the appearance of background color. The screen shots below illustrate the border and background layers pane elements using our sample bronze image. In the examples all pixels other than those in the monument itself have been selected and then deleted so that they are invisible pixels .


images\img_bronze_layers_01.gif images\dlg_bronze_layers_01.gif

The default appearance of invisible pixels is complete transparency, which shows the checkerboard backdrop of all Manifold windows. Without a border it is difficult to see where the image ends.


images\img_bronze_layers_02.gif images\dlg_bronze_layers_02.gif

Checking the Border box will turn on a one-pixel wide black border about the edges of the image. This immediately lets us see the horizontal and vertical size of the image.


images\img_bronze_layers_03.gif images\dlg_bronze_layers_03.gif

Checking the Background box fills in the image window with background color. This shows us what the image will look like if printed or rendered into a graphics format like .gif or .jpg that does not support alpha transparency.


images\img_bronze_layers_04.gif images\dlg_bronze_layers_04.gif

On a white background it may be difficult to tell where the actual image begins and ends. We can check both Border and Background to see how the image looks as well as seeing the extent of the image.


The Layers Pane and Layouts


When a print layout window has the focus the layers pane will show each item in the layout as a layer. Available commands include:


·      Checking a box will turn the layout element on and unchecking the box will turn the layout element off. Hiding an element by unchecking its box will prevent it from being clicked, selected or printed.

·      Moving "layers" up and down in the layers pane will move the layout elements up and down relative to each other within the layout.

·      Double clicking onto a text label in the layers pane will allow immediate editing of the text in the box directly from the layers pane.

·      images\btn_delete_thing.gif The Delete Layer button in the layers pane toolbar will be enabled when any layer except the main layer is clicked. Deleting a layer will remove this element from the layout.

·      images\btn_properties.gif The Properties button in the layers pane toolbar will open the properties dialog for any component-based element in thelayout.


The layers pane is a key control when working with complex layouts.




In the example above we see a layout together with the layers pane. The layout is based on a main element that is a drawing of Europe. Below it is a text element that consist of the phrase "Copyright 2002" repeated several times in an outline font using a light gray color. Above the main element is another text element giving the title, "Europe," and two images, the example Bronze and Schloss images. The Background layer is turned off, so behind the layout page we see the checkerboard pattern used in Manifold when there is no background.


Note that the layout elements added with layout tools, such as text, are shown in the layers pane with special "layout element" icons. Text elements will be named using the initial characters of their text.


With many overlapping elements in a layout we can use the layers pane to turn off upper elements if we want to select or otherwise work with lower elements.


Layouts in the Layers Pane with other Components


If a component has any Layouts created they will appear as "layers" in the layers pane for that component. Checking the box for one of these print layout layers will cause a layout rectangle to appear in the component that shows the region covered by the layout.




In the illustration above the drawing has four layouts that show different parts of Mexico. Three of the layouts have been checked in the layers pane causing three layout preview rectangles to appear in the drawing.


The preview layout rectangles will be automatically adjusted if we change the scope of the layout.




For example, suppose we open a drawing window and a layout window for the same drawing and show the layout in the drawing window by checking the layout layer's checkbox. We select an area in the drawing by clicking on it with Select Touch. The scope of the layout (set by right clicking the layout in the layout window and choosing Properties is set to entire component.




If we now change the scope of the layout to be the selection, the layout will show only the selected objects (one area, Germany, in this illustration) and simultaneously the drawing window will be updated to show the new region covered by this area.


Right clicking onto the hatched border of one of the layout rectangles in the drawing will cause a context menu to appear with controls based on that layout rectangle. For example, we can Zoom to a given layout rectangle, Print it or change its Properties. If a layout is empty (for example, if the layout scope is set to selection and nothing is selected in the parent component) zooming to the layout will do nothing.


Use Tools - Options - Colors - Layout Rectangle to change the color in which layout rectangles are shown. The default color is black.




One way of "seeing" invisible pixels is to use the Selections pane built-in invisible pixels selection and to push in the Preview button in the Selections pane to see any invisible pixels in blue preview color. However, invisible pixels are not the only way to render pixels invisible in Manifold images. If the image is an RGBa image it is possible to select some pixels and to set their alpha channel transparency very high so that they are completely transparent. In this case they are not invisible pixels and will not appear in the invisible pixels system selection in the Selections pane.


Only maps can have true "layers" in Manifold in the sense that they can layer more than one component within the same map window. Neither the border and background "layers" in the Layers pane for drawings and images, nor the channel "layers" in the Layers pane for images are true layers even though they appear in the Layers pane in the same manner as do layers in maps. These are simply system controls that take advantage of the Layers pane as a conceptually convenient user interface.


Layers pane settings apply only to the context window, that is the window that has the focus. For example, suppose we have the same RGB image component open in three image windows and also in view in two opened map windows. If we click on one of the image windows to give it the focus and turn off the Red channel in the Layers pane, the image will immediately change appearance in the context window but will not change appearance in any of the other opened windows. If we then click on one of the other image windows the Layers pane for that window will still have the Red channel turned on.


See Also:


Images and Channels

RGBa Pixel Transparency


Painting within Channels

Separating Images by Channels

Combining Channels into Images