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CSC/FAR 020, Computer Graphics, October 27, 2014. Dr. Dale E. Parson http://faculty.kutztown.edu/parson Outline for Week 9 Vectors and Paths, also File Export. Photoshop Paths. Vector outlines are Paths. Like Type, they are vector shapes. Create them using the Pen and Shape tools.
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CSC/FAR 020, Computer Graphics, October 27, 2014 Dr. Dale E. Parson http://faculty.kutztown.edu/parson Outline for Week 9 Vectors and Paths, also File Export
Photoshop Paths • Vector outlines are Paths. • Like Type, they are vector shapes. • Create them using the Pen and Shape tools. • You can create, save and reuse Shapes (Paths). • Vector Masks are the vector graphical counterparts to Layer Masks. • Vector Masks are sharp, precise, and consume less storage space than layer masks.
Converting a Selection to a Path • Open SymmetryLace.jpg in Folder type. • Crop to the lace projection on the screen. • Select with Magic Wand in New & Add modes. • Display Windows -> Paths. • Make Work Path from paths palette menu or Work path from Selection icon at bottom. • High tolerance gives smoother, more usable shape.
First Use of a Path • Make an empty layer in this document and select it for editing. • Go back to Path palette and Control-Click Fill Path after choosing a foreground color. • Hide the underlying image layer. • Create a middle layer of black foreground. • Try shutting off visibility of all layers.
Manipulating a Path • Highlight the path on the Paths palette. • Select Path Selection Tool (arrow) on Tools palette. • Click small, “island” path on the image. • You can copy and move a path “island.” • Use Direct Selection tool (open arrow) to select anchor points, Shift-click or drag a marquee to select more, Shift-click to remove.
Practice Manipulating Paths • Open RuoriTrapezoid.jpg, duplicate layer. • Use Polygonal Lasso to select the trapezoid. • Convert it to a Path on the Path palette. • Hide image layers. • Use Path Selection (solid arrow) and Direct Selection (open arrow) tools to select, deselect, and manipulate anchor points. • Select and move a single anchor, or a line segment by selecting 2 anchors, or a direction line.
Saving and Using Paths • Get a fresh path that matches the trapezoid. • Drag its anchors to create a rectangle. • Double click the Work Path, rename it. • Control-click the Path, Fill path to fill it. • Stroke path to select a stroke. • Go into that stroke-specific tool first to set the stroking tool configuration parameters.
Pen Tool • Add a new, empty Path. Select pen tool. • Single click to add vertices of a polygon. • Click and drag to create curved segments. • Click start point to close a polygon. • Alt-drag to create non-smooth points. • Enter or Escape to terminate current polygon. Delete/Backspace deletes latest vertex. • Pen options to add or delete anchor points.
Freeform Pen • Magnetic and non-magnetic options. • Magnetic follows edges in an image layer. • Option bar has various shape tools. • Rectangle and ellipse use Shift-drag for symmetry. • Polygon shape has number-of-sides parameter. • Custom shape has library of shapes.
Path to Selection • Control-click a Path, Make Selection. • New / Add / Subtract / Intersect the selection. • Load path as Selection selects just one path.
Vector Masks • Shape-defined masks similar to layer-masks. • Layer -> Vector Mask -> Reveal All, or • Layer -> Vector Mask -> Hide All. • Draw shapes on mask to reveal image area. • Apple-click the mask to make a selection. • You can also create a vector mask from a Path via Layer -> Vector mask -> Current Path. • Rasterizing converts Vector to Layer Mask.
More Vector Masks • Select on basis of a layer mask (Apple-click the Layer Mask thumbnail), then create a Vector mask from Selection. Discard Layer Mask. • Add a Type Layer, then Control-click Convert it to Shape. • You can Edit -> Transform type when it is a Shape. • Select using Vector Mask, Invert the selection, then create an Inverted Vector mask. • Edit -> Define Custom Shape to add to shape library.
PDF • PDF is useful for exporting to word processing tools that cannot read Photoshop files. • Download export.zip, Open Concert1.psd. • Save as PDF without layers or Photoshop editing as Concert1.pdf. • Save as PDF with layers and Photoshop editing as Concert1.pdf. • Load into PowerPoint or Word (Insert -> Picture) and compare quality.
Output for Web • GIF is an 8-bit format, good for up to 256 colors, retains transparency. • JPEG uses 24-bit format with adjustable quality / file size trade-off, no transparency. • Use JPEG for continuous-tone images. • Limit image size to 800 x 600 pixels at 72 ppi for compatibility with browser screen area and resolution. • Smaller file sizes load into browsers faster.
File -> Save for Web and Devices • Allows preview of GIF and JPEG options. • 2-Up and 4-Up tabs support comparisons. • Dithering - Diffusion mixes fewer colors (smaller files) to simulate bigger gamut. • Restrictive color reduction is standard web safe. • Perceptual is biased towards perception. • Selective biases towards colors in the image, compromise between the above two. • Adaptive adjusts to the document, bigger files.
JPEG • Quality parameters trade file size versus image fidelity. • Increasing Blur can reduce noisy artifacts caused by JPEG compression. • Matte substitutes for transparent areas. • Use of either GIF and JPEG usually requires viewing in the context of a browser. • Create / use thumbnails where possible to leave original image at higher resolution.
Inserting images into web pages. • SeaMonkey is a free, open-source browser with HTML editing ability. It comes with an editor. • http://www.seamonkey-project.org/ • Adobe editor is Dreamweaver. • Putting up a simple page to preview is straightforward. Embed an image with some text.
