When creating an object in a map using a tool such as Create Area, right in the middle of the process we can edit coordinates in the Info pane Coordinates tab. This example shows the step by step process.
We begin with a new, blank drawing open in a window. As described in the Editing Drawings topic, we choose Create Area for the mode button in the main toolbar.
In this example, snapping is on, so there is a snap box around the Create Area cursor. We could turn off snapping by pressing the Spacebar. When creating new objects or in editing mode, pressing the Spacebar is a quick keyboard shortcut to toggle snapping on and off.
We click to mark the first vertex of the area. The Info pane automatically appears, showing the Values tab.
We move the mouse over the Info pane, to click on the Coordinates tab to show the list of coordinates being built. The coordinates of the first click appear in blue preview color in the first Coordinates list row.
Moving the mouse back over the drawing window we can continue to draw the area. The editing session stays alive even if we move the mouse away from and then back into the drawing window in which we are editing. We can even move the mouse into a different application, like a web browser, do some work in the web browser, and then when we return to Manifold the edit-in-process will be exactly where we left it.
In the drawing window we click the second vertex location and immediately a second row appears in the Coordinates list.
In the drawing window we click the third location, to add a third vertex and a third row of coordinates.
Suppose that although we are not yet finished with creating the area, we would like to alter the position of the second vertex. We can double-click into the X coordinate box and change the value, pressing Enter when done.
Likewise, to enter a different number for the Y coordinate we can double-click into the Y coordinate box and change the value, pressing Enter when done.
We can move the locations of vertices by changing X and Y coordinate values. If we double-click into the X cell for the first vertex, and we enter the same X value as in the next row, the two vertices will both have the same X values and thus line up vertically.
As soon as we press Enter to finish editing the vertex moves to line up with the vertex above it. While we are at it, we will double-click into the Y cell for that vertex and edit the long coordinate to a more round value.
Suppose now we would like to align the third vertex to the same horizontal location as the second vertex. We double-click into the Y cell for that vertex and enter the same Y value as the preceding vertex.
As soon as we press Enter to finish editing the vertex moves up to the same horizontal, Y level as the preceding vertex. We will edit the X cell for the third vertex as well.
The result is a precise, right angled triangle where all the coordinates for vertices are simple integers.
We are still in Create Area mode, so we an add a fourth vertex to create a rectangle, if we like. We could do that by clicking a fourth time into the map at the approximate location for the fourth vertex, and then we could use the Coordinates pane to even up the coordinates of the fourth vertex to form a precise rectangle.
Or, if we like, we can specify the location of the next vertex by entering values directly into the Coordinates list, if we prefer that to clicking with the mouse in the drawing window.
We double-click into one of the coordinate boxes in the new coordinate row marked by an * asterisk in the row handle.
We enter the same Y value as for the first vertex, so the fourth vertex will be on the same horizontal level.
When adding a new coordinate row if we enter just one of the coordinates and press Enter, the system will auto-complete the second coordinate by copying the corresponding value from the immediately preceding coordinate row. This is a convenient way of adding coordinates that align vertically or horizontally. In this case, when we enter a Y value for the new vertex...
...as soon as we press Enter, the system will auto-complete the new coordinate row by coping the X value from the preceding coordinate row. If we do not like that we can, of course, double-click into the X cell and change the value to whatever we want. Press Add Record to create the area.
We exit Create Area mode by choosing the default navigation setting for the mouse cursor in the main toolbar.
We can see that a new, rectangular area object has been created in the drawing. To confirm the coordinates of the vertices are as we created them, we Alt-click the area and then click the Coordinates tab of the Info pane.
That displays the coordinates for the area object. Note that the very last coordinate of an area is the same as the first coordinate, automatically added when the area was created to close the area boundary that defines the area object.
Clicking on whole number coordinates - Sometimes when creating objects in drawings, or labels in a labels component, for example, when using Manifold as a CAD editor or using Manifold to create diagrams for illustrations, we would like the coordinates we click for objects to be whole numbers, such as X,Y values of -165, 40 and not -165.4954783999, 40.9398312223.
The easiest, explicit way to do that is to use snap modes and set Snap to Grid to using some reasonable even number for Grid step. in the Snap Parameters dialog. A Grid step value of 0.1, for example, will limit mouse clicks to only those grid locations that are tenths of the unit of measure, that is, only one number to the right of the decimal point. This topic used a Grid step value of 1, with Snap to Grid set, so all coordinate numbers were round numbers with no digits to the right of the decimal point.
Blue color used in editing - Objects that are picked for editing, as well as paths drawn by the measurement tool and in editing, have their coordinate edit handles and boundaries shown using the same blue color used for previews and for provisional edits in other settings. If desired, we can change the preview and provisional color used by Manifold in the Tools - Options dialog. This allows us to use a color different than blue color in cases where a visual display already uses very much blue color or to provide a more discernible color in case of color blindness.
User Interface Basics
Example: Layers Tutorial - We take a tour of the Layers pane, learning how to manage layer display order, select layers, turn several layers on and off at the same time, alter opacity settings for one or more layers and how to change background color.
Example: Edit Attributes and Move a Point - We look at the attributes for a point in a drawing layer and edit one of the attributes using a more expanded Edit dialog. We then move the point to a new location. Easy!
Example: Edit Attributes, Larger Text, IME for Asian Languages - A tour showing how to edit attributes in a drawing using the Info pane Values tab and the expanded Edit dialog, including advanced Unicode facilities and use of the built in Input Method Editor (IME) to input text in Japanese language.
Example: Edit Covered Objects - Working with drawings where some areas completely cover smaller areas is a bad idea, but sometimes we have to work with data in that form whether we like it or not. This topic shows techniques that can help us select and edit objects that are completely hidden by higher objects.
Editing Drawings - Create Areas - How to create areas (polygons) in a drawing. We digitize a lake by tracing over a background satellite image layer from a web server. This quick video shows how editing tools in Manifold make it easy to digitize objects very quickly, correcting any errors with no stress or fear of getting it wrong. Includes a quick demo of snapping.
Editing Drawings - Create Lines with Curves - A very short video showing how to create lines in drawings using straight segments and also circular arcs. We create a line in a map of Paris showing our walk around circular ponds. Manifold can create polylines using straight line segments for classic polylines, or using curved segments that are circular arcs, ellipses, or splines for very smooth curves, a much faster and easier technique than clicking many points. Super!