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1.1 root 1: Comments about LINEFRAC
2:
1.1.1.2 ! root 3:
! 4: Notes:
! 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: Two of the modules generate the following warning when they compile:
! 11: warning C4058: address of frame variable taken, DS != SS
! 12: This is the result of a fairly obscure compiler warning message bug,
! 13: which will be fixed in a future release. The emitted code is correct.
! 14:
! 15:
! 16:
! 17: General Description:
! 18: --------------------
! 19:
! 20: This program draws self-similar fractals defined by transformations
! 21: of the unit interval. By recursively applying the transformation,
! 22: neat drawings result.
! 23:
! 24: Currently you can only choose the built-in transforms. Click on one
! 25: to get that fractal at the current level of recursion. Choose level
! 26: one (from the miscellaneous attributes dialog box), and one side to the
! 27: frame polygon (same dialog box), to see the transformation itself.
! 28: Some fractals are shown graphically in the menu.
! 29:
! 30: Clicking on the left mouse button causes the fractal to go deeper
! 31: into recursion, while clicking on the right causes it to come back
! 32: out.
! 33:
! 34: In the misc. attributes dialog box you can specify "# sides of polygon",
! 35: which is the number of initial segments to which your transform
! 36: will be applied. You always get a regular polygon of the number
! 37: of sides you choose.
! 38:
! 39: With the current limited set of transforms, you can still get some
! 40: interesting effects by drawing a new fractal on top of old ones
! 41: with varying attributes. You can also draw several independent
! 42: fractals and automatically switch between them, simulating animation.
! 43:
! 44: Note that at recursion level n, an m-segment transform will be
! 45: n
! 46: composed of m line segments. Keep this in mind when playing with
! 47: the 5-segment transforms, namely StovePipe and SquareWave.
! 48:
! 49: The names are, except for Koch (mathematician who proved, I think,
! 50: that the Koch curve has infinite arc length when the level of recursion
! 51: goes to infinity), weak attempts to describe the basic shape. The
! 52: Fractal menu uses pictures, anyway.
! 53:
! 54:
! 55: Description of commands:
! 56: ------------------------
! 57:
! 58: File
! 59:
! 60: Load ...
! 61: Load a bitmap from a BMP file. The top thread must have a
! 62: memory DC.
! 63: (Currently requires AutoResize option to be enabled).
! 64: Save ...
! 65: Save bitmap to a BMP file. The top thread must have a memory DC.
! 66: About ...
! 67: Show the credits.
! 68:
! 69:
! 70: Edit
! 71:
! 72: Select
! 73: Drag a rectangle (from lower left to upper right) to highlight
! 74: it for cutting or copying. If you don't like what you selected,
! 75: then do it again. Nothing's permanent until you choose cut or
! 76: copy. Hitting the space bar will throw away the selection
! 77: rectangle.
! 78:
! 79: Cut
! 80: Copy the selected rectangle of bits into the "clipboard", and
! 81: fill with the current background color.
! 82:
! 83: Copy
! 84: Copy the selected rectangle of bits into the "clipboard".
! 85:
! 86: Paste
! 87: Copy the cut or copied bits back into the bitmap with the current
! 88: rop. The selected rectangle is highlighted in its original
! 89: location. Grab somewhere in the window (in the highlighted
! 90: rectangle is suggested) and move it to the desired location.
! 91:
! 92: Use Clipboard
! 93: Not implemented yet. This will instruct linefrac to use the
! 94: shell's clipboard feature for saving bits, rather than an
! 95: internal second bitmap.
! 96:
! 97: ----------------------------------------------------------------
! 98:
! 99: Paste w/ S
! 100: DSa
! 101: DSo
! 102: DSx
! 103: Sn
! 104: DSan
! 105: DSon
! 106: DSxn
! 107:
! 108: Various rops for use when pasting bits back into the bitmap.
! 109:
! 110:
! 111: Thread
! 112:
! 113: New
! 114: Direct
! 115: Creates a new thread which draws directly to the screen.
! 116: The WM_PAINT message does nothing for this thread. To
! 117: see the image after the bits have been destroyed, you
! 118: have to cause a redraw (try Control Redraw). Only one
! 119: thread may have a direct DC (temporary restriction).
! 120: Memory ...
! 121: Creates a new thread which draws into a bitmap. If
! 122: thread inheritance is enabled (see below) the bitmap
! 123: parameters are taken from the top thread. Otherwise a
! 124: dialog box appears with the bitmap parameters set to the
! 125: window dimensions with 0 planes and 0 bits per pixel (the
! 126: latter two cause the device to select its favored format).
! 127: The user can alter any of these values as desired. When the
! 128: dialog box is closed, a bitmap is created and a thread
! 129: is created to draw into it.
! 130: PostScript
! 131: not implemented yet
! 132: ProPrinter
! 133: not implemented yet
! 134:
! 135: Bring to top
! 136: Select the number of the thread to bring to the foreground.
! 137: To switch between threads quickly via the keyboard, type a
! 138: digit between 0 and 9. The thread started at that position
! 139: in the overall order will be brought to the front, e.g. its
! 140: bitmap will be visible, in the case of a memory DC thread.
! 141: For a direct DC thread, nothing will happen to the image
! 142: until a redraw is caused.
! 143:
! 144: Edit DC Parameters ...
! 145: View or edit the bitmap extents and color format.
! 146:
! 147: Kill top thread
! 148: Kills the top thread. Brings the next lower (lesser id)
! 149: thread to the top. If there's only one thread, a new
! 150: thread is created with the program defaults.
! 151:
! 152: Kill all threads
! 153: Kills all the threads and leaves the program with one thread
! 154: with the program defaults.
! 155:
! 156: ----------------------------------------------------------------
! 157:
! 158: Automatic cyclic switch
! 159: "Animates" by automatically switching between each thread in
! 160: turn. The delay between switches is set by the next command.
! 161:
! 162: Switch delay ...
! 163: Set the delay in microseconds between switches between threads.
! 164:
! 165: Update menus on thread switch
! 166: This controls the checking or unchecking of the various menu
! 167: items that vary per thread. If disabled, there is less overhead
! 168: in a thread-switch, therefore a faster possible switch time.
! 169:
! 170: ----------------------------------------------------------------
! 171:
! 172: New thread inherits from top
! 173: If enabled, new threads will be copies of the thread which
! 174: was on top when the new thread was started. If disabled,
! 175: the program will select default values for all thread variables.
! 176:
! 177:
! 178: Control
! 179:
! 180: Redraw
! 181: Forces the fractal to be redrawn.
! 182:
! 183: Abort drawing
! 184: Causes drawing of current fractal, if any, to cease.
! 185:
! 186: Clear surface
! 187: Clear the drawing surface to the background color.
! 188:
! 189: Copy bitmap to screen.
! 190: Copies the entire bitmap to the screen. Does nothing for
! 191: a direct DC.
! 192:
! 193: Square up window
! 194: Force the window to be nearly square for aspect ratio-corrected
! 195: drawing.
! 196:
! 197: Resize surface to window
! 198: Resizes the drawing surface to the window dimensions.
! 199:
! 200: ----------------------------------------------------------------
! 201:
! 202: Mouse click changes recursion
! 203: If enabled, clicking in the client area changes the level of
! 204: recursion: left button --> go deeper (higher level);
! 205: right button --> go shallower (lower level)
! 206:
! 207: Animate mouse pointer
! 208: This causes the mouse pointer to change shape as it is moved.
! 209: It represents the koch curve going from recursive level 0 to 3
! 210: and back to 0 again repeatedly.
! 211:
! 212: Mouse pointer preferences ...
! 213: Let's you select the pointer shape to use when the pointer is
! 214: not animated. Let's you determine the speed of animation by
! 215: setting the number of WM_MOUSEMOVE messages tallied before
! 216: switching pointer shapes.
! 217:
! 218: Cyclic redraw timer delay ...
! 219: Sets the delay in microseconds between automatic redraws. Note
! 220: that the timer proceeds independently of the drawing. A long
! 221: fractal will probably end up redrawing immediately, since its
! 222: semaphore will have been cleared before the current drawing is
! 223: finished, that is unless the delay is corresponding long.
! 224:
! 225:
! 226: Fractal
! 227:
! 228: SharkTooth (2 segments)
! 229: SawTooth (3 segments)
! 230: Koch (4 segments)
! 231: StovePipe (5 segments)
! 232: SquareWave (5 segments)
! 233:
! 234: Space filling curve (4 segments) (reflections on first and fourth segs)
! 235: (Note: the space filling curve was originally intended to be drawn
! 236: with the custom primitive "Peano curvelet").
! 237:
! 238: Hourglass (3 segments, crosses itself)
! 239:
! 240: Click on one of these to select a similarity transform for your
! 241: fractal.
! 242:
! 243: ----------------------------------------------------------------
! 244:
! 245: Redraw after change
! 246: If enabled, causes an automatic redraw to occur after any
! 247: selection on this menu.
! 248:
! 249:
! 250: Primitive
! 251:
! 252: PolyLine
! 253: PolyFillet
! 254: PolySpline
! 255: PolyMarker
! 256: Peano curvelet
! 257:
! 258: These determine the primitive used to display the points
! 259: accumulated during recursion on the fractal.
! 260:
! 261: The Peano curvelet is a "custom primitive". It draws two lines
! 262: between each point instead of one. The lines meet at a right
! 263: angle. If the straight line between the two points is x major
! 264: (the difference in x is greater than the difference in y),
! 265: then the new middle point is on the left side, otherwise it's
! 266: on the right side. In other words,
! 267:
! 268:
! 269: * * *
! 270: * * * * ^ * | *
! 271: * * * | * | *
! 272: | * | *
! 273: ----> <---- | * | *
! 274: | * V *
! 275:
! 276: With this primitive, the existing algorithm and data structures
! 277: can be used to draw the Peano space-filling curve. Note that
! 278: the directions of these arrows are relative to the canonical
! 279: unit line segment in world coordinate space on which the
! 280: fractal is really drawn. If the fractal is rotated (to put
! 281: it on the side of a polygon, for instance), the arrows all
! 282: rotate accordingly.
! 283:
! 284: ----------------------------------------------------------------
! 285:
! 286: Redraw after change
! 287: If enabled, causes an automatic redraw to occur after any
! 288: selection on this menu.
! 289:
! 290:
! 291: Attributes
! 292:
! 293: Line attributes ...
! 294: Marker attributes ...
! 295: Area attributes ...
! 296: Image attributes ...
! 297: Set the various attributes.
! 298:
! 299: Miscellaneous attributes ...
! 300: Calls up a dialog box in which you can select the following
! 301: values:
! 302:
! 303: # sides to initial polygon
! 304:
! 305: number of points sent to GpiPolyLine at a time
! 306:
! 307: level of recursion at which to draw
! 308:
! 309: angle of rotation (radians, CCW positive) applied to initial
! 310: segments of fractal
! 311:
! 312: Fractal dimensions ...
! 313: x offset and scale, as a percentage of the width of the window
! 314: same for y, too; the offsets determine where in the window
! 315: the fractal occurs, whereas the scale factors determine
! 316: roughly how big the image is
! 317:
! 318:
! 319: Drag fractal dimensions
! 320: Lets user drag a rectangle in the client window to determine
! 321: the approximate bounding box of the next fractal. "Approximate"
! 322: because fractals might flow out of the box given enough depth
! 323: of recursion. This call alters the values of the scale factors
! 324: and offsets. The fractal attributes dialog box will show the
! 325: new values the next time it is called up.
! 326:
! 327: ----------------------------------------------------------------
! 328:
! 329: Redraw after change
! 330: If enabled, causes an automatic redraw to occur after any
! 331: selection on this menu.
! 332:
! 333:
! 334: Environment
! 335:
! 336: AutoResize bitmap
! 337: If checked, the bitmap will be resized every time you change
! 338: the window size (even if you iconize).
! 339:
! 340: If not checked, the bitmap will stay the same size and won't
! 341: be redrawn when the window size changes.
! 342:
! 343: When the window is resized, each thread will react according to
! 344: this flag.
! 345:
! 346: AutoSelect fractal dimensions
! 347: If this is checked, the default x,y offsets and scale factors
! 348: will be used as soon as the transform is selected. This positions
! 349: the fractal so as to center it in the window, with room to grow
! 350: so that it won't be clipped as the level of recursion increases.
! 351: Note that the space filling curve grows up, not sideways, so it
! 352: is not centered like the others.
! 353:
! 354: Clear surface on redraw
! 355: If enabled, the surface will be filled with the current area
! 356: attributes on the next redraw.
! 357:
! 358: Automatic cyclic redraw
! 359: Sets a timer which after a random delay causes a redraw.
! 360: The upper and lower limits on the random delay are set with
! 361: the "Control Timer delay ..." command.
! 362:
! 363: Collect bounds on fractals
! 364: When this is checked, the minimal rectangle of bits will be
! 365: copied to the screen after a fractal is drawn into the bitmap.
! 366: This speeds up the drawing slightly, and the mouse pointer won't
! 367: flash unless it's right on top of where the drawing is happening.
! 368:
! 369:
! 370:
! 371:
! 372: Bugs to fix:
! 373: ------------
! 374: sometimes the animation timer seems to stop -- moving the mouse over
! 375: the window is enough to get it started again
! 376: occasionally the redraw seems to not work -- selecting it again
! 377: works though
! 378: occasionally a fractal is not drawn to completion
! 379: parts of the window sometimes get erased with the WM_ERASEBACKGROUND
! 380: message, but don't get updated by WM_PAINT. Why? Should
! 381: LfEraseBackground invalidate what it paints for the benefit
! 382: of LfPaint?
! 383: sometimes the upper left of a fractal is displayed in the window
! 384: instead of the lower left, depending on the window dimensions
! 385: (I saw this with a bitmap much larger than the screen) --
! 386: slowly resizing the window reveals a point at which the switch
! 387: occurs
! 388: the "cancel" buttons don't work as expected on various dialog
! 389: boxes -- looking at attributes can cause the fractal to redraw
! 390: even though nothing changes; cancelling the new thread dialog
! 391: box doesn't stop it from being created
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