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Annotation of os232sdk/toolkt20/c/samples/fatpel/readme, revision 1.1

1.1     ! root        1: Comments about FATPEL
        !             2: 
        !             3: 
        !             4: Note:
        !             5: -----
        !             6: 
        !             7: You must run "make opendlg" and include the ..\dll directory in your
        !             8: libpath before attempting to make or execute this application.
        !             9: 
        !            10: 
        !            11: Description:
        !            12: ------------
        !            13: 
        !            14: FatPels displays a "magnified" coordinate space with some object
        !            15: rendered into it.
        !            16: 
        !            17: This program illustrates the diamond metric, which is:
        !            18: 
        !            19:     1) Round control points to the nearest integer.
        !            20:     2) Draw the mathematical object onto an imaginary grid where a diamond
        !            21:        surrounds each pel, the tips of which exactly touch the tips of
        !            22:        similar diamonds around each surrounding pel.
        !            23:     3) If the object drawn enters the diamond of a pel, turn on the pel.
        !            24:     4) In the case of a tie between pels, turn on the lower one
        !            25:        (in whichever dimension has the tie).
        !            26: 
        !            27: Gpi actually restricts this rule by requiring that the object
        !            28: touch the cross drawn between opposing vertices of the diamond.
        !            29: 
        !            30: To see the effect of rendering different objects, click in the window
        !            31: to add control points, or select a different output primitive from the
        !            32: Primitive menu.  You can add points by clicking with the left button,
        !            33: remove them by clicking on them with the right.  If you click on a point
        !            34: and hold the button down, you can drag the point around the window, with
        !            35: the mathematical and rendered curves following you.  You can insert
        !            36: points into a line segment by clicking on the line.
        !            37: 
        !            38: To see the effect of rendering at different scales, resize the
        !            39: pels (menu command: PelSize Set pel size and shape ...).
        !            40: The dimensions of the target coordinate space are determined by how
        !            41: many pels of the given size will fit in the program's window.  The
        !            42: sample control points follow the corners of the target space.
        !            43: Resizing the window will cause a reevaluation of how many pels will fit.
        !            44: 
        !            45: You can "touch up" a rendered object by entering "edit color" mode, by
        !            46: selecting "Colors Edit pel colors".  The cursor shape changes to a
        !            47: hollow diamond to let you know that mouse clicks will affect pel color
        !            48: rather than control point positions.  Click on the left button to set a
        !            49: pel to the foreground color (i.e. color of rendered object), or the
        !            50: right button for the background (i.e. field) color.
        !            51: 
        !            52: You can see the true (subject to the resolution of your monitor)
        !            53: "mathematical" object by disabling rounding of control points.
        !            54: The control points must be rounded for the object to correspond to
        !            55: the rendered pels, according to rule (1), but it might interest you
        !            56: to see how your intended object is distorted.
        !            57: 
        !            58: Note:  I repaint the window by drawing one pel into the lower left
        !            59:        corner, then calling GpiBitBlt to copy it up a column, then
        !            60:        copy the column across to the right.  If the lower left corner
        !            61:        is clipped, then whatever happens to be covering it will get
        !            62:        copied all over the window. This "feature" is for speeding
        !            63:        up the repaint. To clean it up, bring the window to the top
        !            64:        and issue a redraw command.
        !            65: 
        !            66: 
        !            67: Program commands:
        !            68: -----------------
        !            69: 
        !            70: File
        !            71:     Save bitmap ...
        !            72:        Allow current "fatpel" screen to be saved as a BMP format file.
        !            73:        Note:  this command reads the bits that are on the screen, so
        !            74:        if there's garbage in the window, it will be saved.
        !            75: 
        !            76:     About ...
        !            77:        Show the credits and version number.
        !            78: 
        !            79: Display
        !            80:     Rendered object
        !            81:        Display the mathematical object rendered into the small bitmap,
        !            82:        as fat pels.
        !            83: 
        !            84:     Mathematical object
        !            85:        Display the "mathematical" object, i.e. drawn to the original
        !            86:        coordinates in the window, rather than the transformed down
        !            87:        coordinates in the small bitmap.
        !            88: 
        !            89:     Control points
        !            90:        Display markers for the control points.
        !            91: 
        !            92:     Crosshairs
        !            93:        Display the crosshairs in the center of each pel.
        !            94: 
        !            95:     Pel borders
        !            96:        Draw a border (in the crosshair color) around each pel.
        !            97: 
        !            98:     Rounded control points
        !            99:        Round the control points before drawing, to mimic the way
        !           100:        Gpi does it.  To see whether the curve follows the
        !           101:        diamond metric correctly, the mathematical object must be
        !           102:        drawn with its control points rounded to the nearest pel.
        !           103:        Note: Selecting control points is difficult with this option on,
        !           104:        because they are not displayed at their true locations.
        !           105: 
        !           106:     Auto redraw after changes
        !           107:        Automatically redraw the image after any changes.
        !           108: 
        !           109: Primitive
        !           110:     None
        !           111:        Don't draw anything on the grid.
        !           112: 
        !           113:     GpiPolyline
        !           114:     GpiPolyFillet
        !           115:     GpiPolySpline
        !           116:     GpiPointArc
        !           117:        Draw with the given primitive.  In the case of primitives which
        !           118:        require points in groups of a given size (e.g. GpiPolySpline),
        !           119:        some points may be truncated when calling GPI.
        !           120: 
        !           121: Colors
        !           122:     Set colors ...
        !           123:        Allows various colors used by the program to be changed.
        !           124:        In RGB mode, the color values are presented in hexadecimal
        !           125:        notation, since it's easier to see the different color
        !           126:        components that way.  You can still type in decimal numbers.
        !           127:        In RGB mode, dithering is allowed.  Note that when going
        !           128:        from RGB to non-RGB (default color index table) mode, the
        !           129:        values are mapped to their nearest equivalents on your
        !           130:        display device.
        !           131: 
        !           132:     Edit pel colors
        !           133:        Sets the mouse pointer mode to "edit color".  The pointer shape
        !           134:        will change to a hollow diamond.  Click with the left button to
        !           135:        change a fat pel to the rendered object's color.  Click with the
        !           136:        right button to set a pel to the field color.  Select this command
        !           137:        again to return to "edit control point" pointer mode.
        !           138: 
        !           139: PelSize
        !           140:     Set pel size and shape ...
        !           141:        Set the pel size to whatever is desired.
        !           142: 
        !           143:     Drag pel size
        !           144:        Allows the pel size to be specified by dragging a rectangle on the
        !           145:        window.  The rectangle must be dragged from lower left to upper
        !           146:        right.  The cursor will change when a button is held down, and
        !           147:        a tracking rectangle will appear.  Clicking in the window with
        !           148:        this option on will cause the pel to be resized to 1 by 1.
        !           149: 
        !           150: Redraw
        !           151:        Redraw the screen with the current selections.

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