CSC/FAR 020, Computer Graphics, September 10-15,

2014Dr. Dale E. Parson

http://faculty.kutztown.edu/parsonOutline for week 3

Changing Canvas Sizeand Crop Tool

• Retrieve CropLayerSelect.zip from Parsons -> Outbox and unzip on desktop. Browse using the Bridge.

• Open NIME2009GeOcarina.jpg in Photoshop.• Image -> Canvas Size to shrink or grow the canvas.

• Undo changes, try again.

• Use Crop Marquee to crop the image.• Make sure Options Width, Height and Resolution are Clear.• Shield option highlights area to crop.• Crop area can be resized, moved, or rotated.• Use Enter or Control-click to accept, Escape to cancel.• Width and Height can set aspect ratio.

Using Crop Tool to Copy Image Size

• Save a smaller version of NIME2009GeOcarina.jpg as WxH.psd (5X7.psd) in inches.

• With WxH.psd still open after saving, open Nime2009Trombon1.jpg from the Bridge.

• In Crop Tool click Clear and Front Image from within 5X7.psd. Now crop Nime2009Trombon1.jpg, rotating marquee to get alignment.

• Get both images to the same size.• Set background to black and enlarge the 5X7.psd to a size that

can hold both images by stretching crop region.• Select -> All on the trombonist, paste and position into a layer.

Regular Marquee Cropping

• Select and area with the Marquee selector.• Optionally constrain size of Ratio.

• Image -> Crop to crop from here.• Image -> Trim trims away fixed color margins.• Ruler Tool (grouped with Eyedropper) allows

you to orient along some alignment feature.• Image -> Image Rotation -> Arbitrary rotates

to this line.

Layers

• Merge the pair of layers in WxH.psd via the Layers command.

• Sweep a marquee.• Create a new Layer via Copy from Layer menu.• Undo, try the same with Layer via Cut.• Convert background to a layer and back.• Layer groups are like Folders. They are useful

for maintaining layers.

Basic Selection

• Open NVLakeFireFigure.jpg from Bridge.• Select -> All selects all pixels in layer.

• Note other selection options.

• Rectangular and Elliptical Selection tools:• Options on option bar, go into Refine Edge and explore.

• Lasso Tools allows rough selection• Note new/add/subtract/intersect options.• Shift-sweep also adds to selection.• Alt/Option-sweep subtracts from selection.

Polygonal and Magnetic Lasso

• Draw straight-edge polygons around area,• Double-click anywhere or single-click start point to end.• Delete key cancels last vertex (last point clicked).• Alt/option sweeps reverts to free-form lasso.

• Magnetic lasso assists using edge detection.• Delete and alt/option also work here.• Sometimes it closes its own areas based on boundaries.• Use zoom (command + and command -) with this.

Selections Based on Color

• Go to original NVLakeFireFigure.jpg .• Clear selections.

• Use Quick-Selection tool to select the sky.• Auto-enhance to improve edge detection.• Change brush area to sample larger range of pixels.• Add sky and subtract clouds, etc.• Use magnetic lasso + and – for fine tuning.

• Magic wand selects pixels using nearby colors.• Lower tolerance is more selective.• Control-click Similar to add non-adjacent regions.

Silhouette

• Create new image with black background.• Select All -> copy and paste a new layer.• Use color-based tools to Delete portions of

image.

Select -> Color Range

• Selects based on pixel values with a range of fuzziness. NVLakeFireFigure.jpg:

• Select the sky within some range of color values.• Vary Color Range and “Refine Edge” option

parameters.• Select -> Inverse, then Marquee subtraction and Magic

Wand subtraction to get the rock Figure only.

• Edit -> Copy, Layer -> New from Copy.• Save As Dali.psd.

Get rid of the pesky text.

• Edit the new Layer that we just created.• Zoom in and use Magic Wand to select text.

• Cut it to transparent background.

• Use Select -> Color Range and Marquee Intersection to select & delete black smudges in the text borders.

• Use Magic Wand to get a letter’s shape, slide the selection, copy some nearby pixels, then paste them back onto the letter.

• Merge the two working layers and repeat, smudge.

• Use Clone Stamp to tweak. Watch out for feathering!

Adding layers

• Add a series of layers from other photos.• Select all -> Copy -> Paste (across image files).• Drag a layer from one image to another

• Use cloudy Kutztown sky to fill transparent sky layer.

• Size layers using crop tool set to target image dimensions.

• Stack additional, semi-transparent monochrome layers.