Image Editing Tools

Image editing in Manifold uses several controls at once to achieve exactly the desired effect. To edit images we can choose:


·      Image menu commands. These commands perform global changes on the image or the selected area, such as changing hue or contrast. See the Image Menu topic.

·      Transform toolbar commands. These are simple commands or one-line versions of Image menu commands that change the entire image or just the selected area. See the Transform Toolbar - Images topic.

·      Editing tools. These are found on the Tools toolbar for image and provide a variety of free hand and assisted editing capabilities.


Editing Tools


When we paint into an image, we choose a tool and then set any options for that tool.


·      Tools are selected from editing toolbars.

·      The specific action of tools is set in the Format Toolbar or in the Tool Properties pane.


The Tools Properties pane should be kept open when editing images so that parameters can be changed as desired.


To Edit an Image:


1. Choose a tool.

2. Adjust tool properties (such as color to be used) in the Tool Properties pane.

3. Use the tool in the image.


Tools Toolbar for Images




The Tools toolbar for images hosts the image editing tools. Image editing tools are for the most part analogous to drawing editing tools. There are a few modifications specific to the pixel nature of images.



Paint Areas - A mode button: the selected tool will create filled regions of pixels.


Paint Lines - A mode button: the selected tool will create lines.


Paint Points - A mode button: the selected tool will create points where the mouse cursor changes direction on clicks.


Paint Area - Paint pixels within the region clicked. Creates lines or points if shape modes so specify.


Paint Freeform - Paint pixels within region about which the mouse is clicked and dragged.


Paint Line - Paint a line defined by straight-line segments between clicks.


Paint Box - Paint a rectangular box using a mouse click and a drag.


Paint Box on Center - Paint a rectangular box centered on initial mouse click.


Paint Circle - Paint a circle using a mouse click and a drag.


Paint Circle on Center - Paint a circle centered on initial mouse click.


Paint Ellipse - Paint an ellipse using a mouse click and a drag.


Paint Ellipse on Center - Paint an ellipse centered on initial mouse click.


Brush - Paint a dot with one click or a continuous line with a click and a drag. Paints unsmoothed freeforms even if smoothing is turned on. Very useful for single pixel editing (click on a pixel to color it) at high zooms.


Paint Bucket - Click to fill a contiguous region of similarly colored pixels with foreground color. Fills to a given tolerance value of color.

SHIFT click to pour into the given color in all regions of the image within the given tolerance, even if not contiguous. Use this as a "replace color" operation.

CTRL click to replace colors within the threshold while retaining the same intensity.

ALT click to paint color without regard to threshold. Used to fill the entire selection or the entire image (enabled if a snap mode is not set).

CTRL and SHIFT or CTRL and ALT may be combined.


Gradient - Click, drag and release to create a color gradient from foreground color to background color between the click point and ending at the release point.


Pick Color - Click to pick the color at that location as the foreground color.

Shift click to pick the color at that location as the background color.


Regular and On-Center Commands


Like selection tools, painting tools occur in both on-center and regular versions. We can see the difference between the regular tool and the on-center tool by painting a circle.


images\img_tools_alt_key_01.gif images\img_tools_alt_key_02.gif


images\btn_paint_circle.gif Using Paint Circle to click near the center of the monument above and then dragging to the spot shown will open a preview circle as shown. Releasing the mouse button paints within the indicated preview circle. With regular commands, the mouse shows the desired diameter of the circle. The Paint Circle command appears by default on the Tools toolbar for images.


images\img_tools_alt_key_03.gif images\img_tools_alt_key_04.gif


images\btn_paint_circle_center.gif We can use Paint Circle on Center to click at the same beginning location and then drag to the same ending location. Note that the preview circle is larger than the previous circle. With on-center versions of commands the initial click is the center of the circle and the mouse motion shows the desired radius of the circle. Use this command to draw circles centered on a given spot.


Frequently used controls



Pick one of the editing tools from the tools toolbar. The choice of tool sets overall behavior, such as whether each click results in a point or whether we create a rectangle by dragging open a mouse box.


Manifold has many brush styles that may be selected in the format toolbar. Combinations of different brushes with different tools will result in different painting effects.


Most tools use only foreground color, as set in the format toolbar.


The Size parameter in the format toolbar specifies the size of points and the width of lines in pixels. It is applied to enlarge or decrease the size of brush used. Some brushes require a certain minimum size or are constrained to an even number of pixels plus one. When such brushes are used the Size parameter will automatically jump only between allowed values.

Paint Mode

The paint mode buttons in the tools toolbar specify if areas, lines or points are painted when the tool is used. The use of paint modes with images is directly analogous to the use of shape modes with drawings.


Tool Properties and Images


When an image window has the focus the Tool Properties pane sets options used with painting and selection tools for images. See, for example, Editing Images .



A technical parameter that defines the relative height of the density curve used for tools that paint pixels using a curve to define the amount of paint applied. Similar in visual effect to the "hardness" tool parameter in PhotoShop.


Used with selection, paint bucket fills, etc. Specifies how close a color must be to the color specified before it is considered the same color. Increasing the tolerance value will allow colors that are less and less similar to the touched color to be considered the same.




Brushes specify different patterns in which paint is applied. They have a distinct visual effect when painting points or lines. Areas are always filled with solid color when painting filled regions such as a rectangular box.




Varying tools, colors brushes and size can result in dramatically different visual appearance. The above illustration shows different brushes in different sizes applied with different colors. Reduced to 256 colors to fit into this Help documentation it is but a pale rendering of the original, vivid True Color image. Create your own to see what we mean.




When painting lines brushes will have the same effect as if they were dragged in the direction the line is painted. The illustration shows lines drawn using a fuzzy round brush in different colors and sizes.




Changing the size parameter changes the size of points and the thickness of lines. It has no effect when creating filled regions of pixels using area commands.




The illustration above shows a brush used to make points with several different size settings, a box command using two different size settings for the line, and a single pixel sized curly line drawn freehand.


Paint Mode


Just like drawings, editing tools in images can automatically create their desired effects as combinations of points, lines or areas. In images, of course, these are not objects but just point-shaped, line-shaped or area-shaped regions of pixels. The main use of paint modes is to specify whether shapes such as boxes, circles or ellipses are created using outlines or as filled regions.


Graphics editors will often have separate commands for creating an outlined rectangle or a filled rectangle. Other graphics editors always create an outlined rectangle and expect that the user will use a paint bucket command to fill the rectangle if a filled rectangle is desired.




Manifold specifies how a rectangle should be created by whether the Paint Lines or Paint Areas button is pushed in. Pushing in the Paint Areas button creates a filled region of pixels with sharp edges like the box on the right in the illustration above. Pushing in the Paint Lines button only will create the region as an outline using whatever brush is specified in Tool Properties to create the line. A box created using a square brush illustrated at left in the illustration above.




Pushing in both the Paint Areas and the Paint Lines button will result in a filled region that is outlined by a line using the given brush style. The illustration above shows various combinations of the Paint Areas, Paint Lines and Paint Points shape modes using a fuzzy round brush set to a size of 20 pixels.




Tools will paint using whatever brush has been selected. The box at left in the illustration above was painted using a round brush for the line. The box at right was painted using a square brush for the line. Note that the square brush results in sharp corners when a Size greater than one is used and a round brush results in round corners.


Note that using a size larger than 1 pixel together with the Line button will result in a region that is larger that the centerline indicated by the mouse since lines are drawn on centerline. A line fatter that one pixel will extend out from the centerline drawn.


Automatic Paint Modes


By default, the Tools - Options parameter Automatic Paint Modes is checked ON. Automatic Paint Modes will automatically switch paint modes whenever a new image editing tool is chosen to provide the most likely paint mode for that tool. For example, when Automatic Paint Modes is ON, pressing Paint Line will automatically push in the Paint Lines mode button and push out the Paint Areas and Paint Points buttons. This default choice may be overridden by choosing whatever combination of paint modes is desired after choosing the tool.


For example, when Automatic Paint Modes is ON the Paint Areas and Paint Box, Circle, and Ellipse commands will paint areas of pixels only. To paint lines and points as well simply push IN the Paint Lines or Paint Points buttons after choosing these tools.




Some brushes use a mathematical curve to define the amount of paint sprayed into various locations of the brush. The Density factory specifies the proportional difference between the maximum and minimum amount of ink sprayed into different parts of the brush as defined by the curve. In effect, it is either flattening or accentuating the curve.




The effect of increasing this factor is to give a greater appearance of paint density, hence the name of the parameter. The illustration above shows a typical curve-defined brush used to create a "point" with the density factor used for each example printed below in white. At low density the difference between the different regions of the brush are greatest and so it appears as a less dense brush. With high density there is less difference between paint applied throughout the brush and so the brush has a denser appearance.




Opacity works with all brushes. By varying Opacity it is as if we have painted the brush on a layer above the image and then varied the transparency of the layer and then merged the two layers to achieve the final pixel color for each pixel.




The illustration above shows application of a brush where the Opacity of the top row is greatest (100) while the Opacity of the lowest row is only about 30. In all three rows the three yellow applications of the brush were made on top of the same cyan line. To allow comparison with Density, in each of the three rows the Density has been increased from left to right.


Note that Opacity is different than Density. The Opacity parameter applies evenly throughout the entire brush. By varying Opacity the entire brush effect is more or less transparent in an even way throughout the entire brush. Density changes the relationship within the brush.