Csc far 020 computer graphics september 12 2012
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CSC/FAR 020, Computer Graphics, September 12, 2012. Dr. Dale E. Parson Outline for week 3. Changing Canvas Size and Crop Tool. Retrieve from Parsons -> Outbox and unzip on desktop. Browse using the Bridge.

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Csc far 020 computer graphics september 12 2012

CSC/FAR 020, Computer Graphics, September 12, 2012

Dr. Dale E. Parson

Outline for week 3

Changing canvas size and crop tool
Changing Canvas Sizeand Crop Tool

  • Retrieve 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
    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
    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
    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
    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
    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
    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
    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
    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.