Code:
<code lang="sc"> (The lang= is optional)
- .flash
- .box b1 100 100
- .end
+ .flash
+ .box b1 100 100
+ .end
</code>
Tables:
-->
-<chapter><title>swfc Basics</title>
+<chapter title="Basic usage of swfc">
<section><title>Calling swfc</title>
</p>
- <note>
- Though swfc is a command-line utility, there also exists a nice graphical
- frontend for it, called Swifty.
- </note>
-
</section>
<section><title>A simple swfc example</title>
<p>
- Let's create simple SWF file, shall we?
+ Let's create a simple SWF file, shall we?
The following script creates a red box with a yellow border. On the right side you
see the script used, on the left side the swf file that is generated.
</p>
<code lang="swfc">
-.flash name="box.swf"
+.flash filename="box.swf"
.box b1 100 100 color=yellow fill=red
.put b1 pin=center scale=0%
.frame 100
<code lang="swfc">
-.flash name="cxform.swf" version=5
+.flash filename="cxform.swf" version=5 fps=25
.jpeg s1 "photo.jpeg" quality=80%
.put s1 x=50 y=50 scalex=110 scaley=110
- .frame 100
+ .frame 50
.change s1 x=0 y=0 scalex=210 scaley=210 red=-1+255 green=-1+255 blue=-1+255 #invert
- .frame 200
+ .frame 100
.change s1 x=100 y=50 scalex=110 scaley=110 red=0 green=+0 blue=+0 #remove red
- .frame 300
+ .frame 150
.change s1 x=0 y=0 scalex=210 scaley=210 red=+0 green=2 blue=-1+255 #amplify green, invert blue
- .frame 400
+ .frame 200
.change s1 x=50 y=100 scalex=110 scaley=110 red=2-128 green=-2+255 blue=+0.7+40 #alien glow
- .frame 500
+ .frame 250
.change s1 x=0 y=0 scalex=210 scaley=210 red=8-1024 green=8-1024 blue=8-1024 #palette reduce
- .frame 600
+ .frame 300
.change s1 x=0 y=0 scalex=210 scaley=210 red=+0 green=+0 blue=+0 #back to normal
- .frame 700
+ .frame 350
.change s1 x=105 y=105 scalex=0 scaley=0 luminance=0 #fadeout
.end
</code>
</chapter>
-<chapter><title>Fonts</title>
+<chapter title="Fonts">
<section>
For example, for the obligatory hello world program:
<code lang="swfc">
-.flash name="helloworld.swf"
+.flash filename="helloworld.swf"
.font Arial filename="Arial.ttf"
.text helloworld font=Arial text="Hello World!"
.end
</code>
-<notice>
+<note>
The text argument expects UTF-8 strings. So if you want to
pass any special characters (umlauts, digraphs etc.), they have to
be UTF-8 encoded.
-</notice>
+</note>
Besides TrueType fonts, swfc also supports native SWF fonts.
If you have a SWF with a font you would like to use, do a
</p>
<code lang="swfc">
-.flash name="fontoutline.swf"
+.flash filename="fontoutline.swf"
.font Arial "Arial.swf"
.textshape helloworld font=Arial size=200% text="Hello World"
- .filled filled_helloworld outline=helloworld fill=blue line=5 color=green
+ .filled filled_helloworld outline=helloworld fill=blue line=3 color=green
.put filled_helloworld
.end
</code>
of a plain color:
<code lang="swfc">
-.flash name="fontgradient.swf"
+.flash filename="fontgradient.swf"
.font Arial "Arial.swf"
.textshape helloworld font=Arial text="SHADE"
.gradient whitefade:
- 0% black
- 50% #505050
- 100% yellow
+ 0% black
+ 50% #505050
+ 100% yellow
.end
.filled filled_helloworld outline=helloworld fill=whitefade line=1 color=#2c2c2c
While at it, you can also fill with an image:
<code lang="swfc">
-.flash name="fontimage.swf"
+.flash filename="fontimage.swf"
.font courier "Courier.swf"
.jpeg beach "beach.jpg"
.textshape text font=courier text="HOLIDAY"
them for clipping:
<code lang="swfc">
-.flash name="text5.swf"
+.flash filename="text5.swf"
.font courier "Courier.swf"
.text hithere text="HELLO" font=courier size=200%
-.swf scene Scenery50.swf
+.jpeg scenery "scenery.jpg"
-.frame 0
+.frame 1
.startclip hithere pin=center x=100 y=75 scale=50% #text clips...
- .put scene # ...the image "scene"
+ .put scenery scale=50%
.end
.frame 100
.change hithere rotate+=360 pin=center scale=100%
The last two examples look similar, but their underlying structure
is different: The first is a shape object filled with
image data (that is, a texture), while the second uses a normal
-text object to clip an rectangular image.
+text object to clip an rectangular image. (More about clipping in
+the next section)
</p>
<p>
</p>
<code lang="swfc">
-.flash name="text6.swf"
+.flash filename="text6.swf"
.font times "Times.swf"
-.text hello text="HELLO" font=times size=100% color=blue
-.text world text="WORLD" font=times size=100% color=red
+.text hello text="HELLO" font=times size=200% color=blue
+.text world text="WORLD" font=times size=200% color=red
-.frame 0
- .put hello pin=center x=50 y=50
- .put world pin=center x=50 y=50 alpha=25%
+.frame 1
+ .put hello pin=center x=50 y=50
+ .put world pin=center x=50 y=50 alpha=25%
.frame 200
.change hello rotate+=360 pin=center alpha=25%
.change world rotate-=360 pin=center alpha=100%
</section>
-<section>
+<section title="Clipping">
+
+Another example for clipping against text:
+
+<code lang="swfc">
+.flash filename="textclip.swf" bbox=400x120 background=black version=6
+.font times "Times.swf"
+.textshape helloworld text="HELLO WORLD" font=times size=300%
+.filled helloworld1 outline=helloworld fill=blue line=0
+.filled helloworld2 outline=helloworld fill=green line=0
+
+.frame 1
+.put h3=helloworld1 y=100
+.startclip h1=helloworld1 y=100
+ .put h2=helloworld2 y=100
+.end
+
+.frame 1000
+.change h1 x=-1000
+.change h2 x=-500
+.change h3 x=-1000
+.end
+</code>
+
+</section>
+
+<section title="Edittext">
A special type of text in SWF is the <c>edittext</c>, which
can be modified by the viewer. It's content can also be queried
You can generate this type of text with the <c>.edittext</c> command:
<code lang="swfc">
-.flash name="edittext.swf" bbox=210x110
+.flash filename="edittext.swf" bbox=410x210
.font Arial "Arial.swf"
- .edittext myedittext font=Arial size=20%
- width=200 height=100
- color=blue border multiline wordwrap
- text="Edit me!\nClick with your mouse on this text to edit it."
+ .edittext myedittext font=Arial size=50%
+ width=400 height=200
+ color=blue border multiline wordwrap
+ text="Edit me!\nClick with your mouse on this text to edit it."
.put myedittext x=3 y=3
.end
</code>
</section>
+</chapter>
+
+<chapter title="Shapes">
+
+<section title="Creating Outlines">
+
+In the previous chapter, we learned how to create a text outline
+using <c>.textshape</c>. The other way to create outlines is to
+use the .outline command:
+
+<code lang="swfc">
+.flash filename="house.swf"
+
+ .outline house_outline:
+ M 36.99 29.93 L 15.52 51.39 L 20.44 51.39 L 20.44 81.91
+ L 39.73 81.91 L 39.73 62.33 L 48.36 62.33
+ L 48.36 81.91 L 53.84 81.91 L 53.84 51.39
+ L 58.45 51.39 L 36.99 29.93
+ M 28.79 53.70 L 34.55 53.70 L 34.55 60.60 L 28.79 60.60
+ L 28.79 53.70
+ .end
+ .filled house outline=house_outline fill=grey color=grey
+ .put house
+.end
+</code>
+
+The syntax of the paths inside the <c>.outline</c> command is the same as in svg.
+That means you can use the svg editor of your choice (e.g.: <a href="http://inkscape.sourceforge.net">inkscape</a>)
+to create these outlines. You then need to extract them out of the .xml/.svg file.
+They are inside the "d" attribute of the "path" tag:
+
+<code lang="xml">
+...
+ <path
+ style="fill:#0000ff;fill-opacity:0.75000000;fill-rule:evenodd;stroke:#000000;stroke-width:1.0000000pt;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1.0000000;"
+ d="M 369.90625 299.31250 L 155.21875 513.96875 L 204.40625 513.96875 L 204.40625 819.15625 L 397.31250 819.15625 L 397.31250 623.37500 L 483.68750 623.37500 L 483.68750 819.15625 L 538.40625 819.15625 L 538.40625 513.96875 L 584.56250 513.96875 L 369.90625 299.31250 z M 287.90625 537.00000 L 345.50000 537.00000 L 345.50000 606.09375 L 287.90625 606.09375 L 287.90625 537.00000 z "
+ id="rect908" />
+...
+</code>
+
+</section>
+
+<section title="Filling Outlines">
+
+Outlines can be filled with gradients, bitmaps etc., just like
+seen previously with <c>.textshape</c>:
+
+<code lang="swfc">
+.flash filename="gradients.swf"
+
+ .outline star:
+ M 521,640 C 502,678 370,546 328,554 C 270,566 152,731 93,722
+ C 51,716 147,549 127,512 C 98,460 -107,400 -117,341
+ C -124,299 63,339 93,308 C 133,265 127,50 180,23
+ C 218,3 238,195 276,213 C 330,238 532,166 575,208
+ C 605,238 429,316 424,358 C 416,417 547,587 521,640
+ .end
+
+ .gradient rainbow:
+ 0% blue
+ 25% green
+ 50% yellow
+ 75% orange
+ 100% red
+ .end
+
+ .gradient fire radial:
+ 0% white
+ 50% yellow
+ 100% red
+ .end
+
+ .gradient horizon:
+ 0% cyan
+ 49% blue
+ 50% green
+ 100% peru
+ .end
+
+ .gradient transparent:
+ 0% #ff000000
+ 100% #ff0000ff
+ .end
+
+ .box scenery fill=horizon width=200 height=200
+ .box bar fill=transparent width=240 height=20
+ .filled star1 outline=star fill=rainbow line=1
+ .filled star2 outline=star fill=fire line=1
+
+ .put scenery rotate=90%
+ .put star1 scale=10% x=-70
+ .put star2 scale=10% x=-180 y=110
+ .put bar x=-180 y=10 rotate=45
+.end
+</code>
+
+<!-- TODO: bitmap filling -->
+
+</section>
+
+<section title="Some more words about gradients">
+
+<p>
+The previous example demonstrated how to fill an outline with
+a gradient.
+</p>
+
+<p>
+There are two types of gradients: radial and linear. radial gradients
+have a center point and a radius (and are immune to rotations), and
+linear gradients have a start point and a width (or height) and can
+be rotated.
+</p>
+
+gradients can be freely positioned inside the object
+you want to fill, by passing the <c>x</c>, <c>y</c> and <c>width</c> and <c>height</c> (or <c>r</c>) parameters
+to <c>.gradient</c>.
+
+<code lang="swfc">
+.flash filename="gradients2.swf"
+
+ .outline o:
+ moveTo -50,-50
+
+ lineTo 0,-45
+ lineTo 50,-50
+
+ lineTo 45,0
+ lineTo 50,50
+
+ lineTo 0,45
+ lineTo -50,50
+
+ lineTo -45,0
+ lineTo -50,-50
+ .end
+
+ .gradient horizon1 radial x=-50 y=-50 r=100:
+ 0% cyan
+ 49% blue
+ 50% green
+ 100% cyan
+ .end
+
+ .gradient horizon2 radial x=0 y=0 r=50:
+ 0% cyan
+ 49% blue
+ 50% green
+ 100% cyan
+ .end
+
+ .filled o1 outline=o fill=horizon1 line=0
+ .filled o2 outline=o fill=horizon2 line=0
+
+ .put o1 x=50 y=50
+ .put o2 x=150 y=50
+
+.end
+</code>
+
+If you want to use a given gradient several times
+with different <c>x</c> and <c>y</c> values, you can also first
+define the gradient itself, and then position it with .texture:
+
+<code lang="swfc">
+.flash filename="gradients3.swf"
+
+ # same outline as above, only in more terse notation
+ .outline o:
+ M -50,-50
+ L 0,-45 L 50,-50
+ L 45,0 L 50,50
+ L 0,45 L -50,50
+ L -45,0 L -50,-50
+ .end
+
+ .gradient horizon radial:
+ 0% cyan
+ 50% blue
+ 50% green
+ 100% cyan
+ .end
+
+ .texture horizon1=horizon x=-50 y=-50 r=100
+ .filled o1 outline=o fill=horizon1 line=0
+ .put o1 x=50 y=50
+
+ .texture horizon2=horizon x=0 y=0 r=50
+ .filled o2 outline=o fill=horizon2 line=0
+ .put o2 x=150 y=50
+
+ .texture horizon3=horizon x=0 y=50 r=10
+ .filled o3 outline=o fill=horizon3 line=0
+ .put o3 x=50 y=150
+
+ .texture horizon4=horizon x=50 y=50 r=200
+ .filled o4 outline=o fill=horizon4 line=0
+ .put o4 x=150 y=150
+
+ .gradient bunt:
+ 0% black
+ 20% blue
+ 40% magenta
+ 60% orange
+ 80% cyan
+ 100% white
+ .end
+
+ .texture bunt1=bunt x=-50 y=-50 width=100
+ .filled oo1 outline=o fill=bunt1 line=0
+ .put oo1 x=50 y=250
+
+ .texture bunt2=bunt x=-50 y=-50 width=141 height=141 rotate=45
+ .filled oo2 outline=o fill=bunt2 line=0
+ .put oo2 x=150 y=250
+
+ .texture bunt3=bunt x=-50 y=50 width=141 height=141 rotate=-45
+ .filled oo3 outline=o fill=bunt3 line=0
+ .put oo3 x=50 y=350
+
+ .texture bunt4=bunt x=50 y=50 width=100 rotate=180
+ .filled oo4 outline=o fill=bunt4 line=0
+ .put oo4 x=150 y=350
+
+.end
+</code>
+
+
+<!-- TODO: bitmap filling -->
+
+</section>
</chapter>
-<chapter><title>ActionScript</title>
+
+<chapter title="ActionScript">
<section>
<c>swfc</c> has Actionscript support.
the ActionScript into the block:
<code lang="swfc">
-.flash name="action.swf" bbox=300x300 fps=50
+.flash filename="action.swf" bbox=300x300 fps=50
.box mybox color=blue fill=green width=100 height=100
.put mybox
-.frame 0
- .action:
- _root.angle += 0.1;
- mybox._x = 100*Math.cos(_root.angle)+100;
- mybox._y = 100*Math.sin(_root.angle)+100;
- .end
.frame 1
.action:
- gotoFrame(0);
- Play();
+ _root.angle += 0.05;
+ mybox._x = 100*Math.cos(_root.angle)+100;
+ mybox._y = 100*Math.sin(_root.angle)+100;
.end
.frame 2
+ .action:
+ gotoFrame(0);
+ Play();
+ .end
+.frame 3
.end
</code>
-Or, for much more interesting ActionScript examples, see
+For much more interesting ActionScript examples, see
Laurent Lalanne's
<a href="http://technoargia.free.fr/swftools/examples/flash_eyes/flash_eyes.html">Flash Eyes</a>
or the
<a href="http://melusine.eu.org/syracuse/flash/20040429/fabrique/">source</a>
of Jean-Michel Sarlat's
<a href="http://melusine.eu.org/syracuse/flash/20040429/">Mandelbrot explorer</a>.
+or
+<a href="http://www.goldenxp.com/repo/swfr/index.htm">Sunder Iyer's swfc pages</a>.
</section>
</chapter>
-<chapter><title>Buttons</title>
+<chapter title="Buttons">
<p>
Actionscript comes in handy when dealing with SWF Buttons.
</p>
The following is a trivial example: Four objects which change their shape
once the cursor is over it.
<code lang="swfc">
-.flash name="button1.swf" fps=50
+.flash filename="button1.swf" fps=50
.box box1 color=white fill=#336633 width=50 height=50
.box box2 color=white fill=#99cc99 width=100 height=100
.show box2 as=hover x=12.5 y=12.5
.end
-.frame 0
+.frame 1
.put b1=mybutton1
.put b2=mybutton1 x=100 red=+255
.put b3=mybutton1 y=100 green=+255
What exactly is <i>"inside"</i> is defined by <b>area</b>:
</li><li><b>area</b> This shape is not displayed. It serves as bounding box (actually,
bounding polygon) for the button. A button considers itself
- active (that is, the <c>hover</c> shape is active, not the <c>idle</c>
- shape) if the mouse is inside this area. Also, mouse button clicks
- have to be in this area for this button.
+ active (that is, the <c>hover</c> shape is active, not the <c>idle</c>
+ shape) if the mouse is inside this area. Also, mouse button clicks
+ have to be in this area for this button.
</li><li><b>pressed</b> The shape to display if the user clicks on the button. This shape
is displayed as long as the mouse button is down.
</li>
</ul>
</p>
+<!-- TODO: button actionscript -->
+
<!--
<section><title>Another button example: tooltips</title>
outside the active area, it's easy to generate tooltips or subtitles.
<code lang="swfc">
-.flash name="tooltips.swf" fps=50
+.flash filename="tooltips.swf" fps=50
.jpeg pic fence.jpg
.put pic
.show tooltip_fence as=idle x=25 y=25 scalex=100 scaley=100 alpha=50%
.end
-.frame 0
+.frame 1
.put mybutton1
.end
</code>
</chapter>
+<chapter title="Blend Modes">
+
+Blend modes were introduced in Flash 8. They allow to use different alrithmetrics when
+it comes to putting transparent (or semi transparent) shapes or images on top of each
+other.
+The diffent blend modes are:
+
+<shell>
+normal
+layer
+multiply
+screen
+lighten
+darken
+add
+substract
+difference
+invert
+alpha
+erase
+overlay
+hardlight
+</shell>
+
+For example, in order to set a "invert" blend mode:
+
+<code lang="swfc">
+.flash filename="invert.swf" fps=50 bbox=511x127
+.jpeg pic stripe.jpg
+.put pic
+.font arial Arial.ttf
+.text txt font=arial text="Test inverted blend mode... ABCDEFGHIJKLMNOPQRSTUVWXYZ" size=200%
+
+.put txt x=512 y=120 blend=invert
+.frame 700
+.change txt x=-4096
+.end
+</code>
+
+The <c>layer</c> blend modes is especially useful, if you want to
+make sprite transparent. Compare the two stacks of rectangles
+in the next example. In the left one (set without <c>layer</c>), when
+the sprite is made transparent via <c>alpha=50%</c>, the rectangles
+also are transparent in respect to each other- i.e., you don't get
+a transparent image of a stack of rectangles, you get an image
+of a stack of transparent rectangles. On the right side, the
+stack is set with <c>layer</c>, and only the whole sprite get's
+transparent.
+
+<code lang="swfc">
+.flash filename="layer.swf" fps=50 bbox=511x127
+.jpeg background stripe.jpg
+.put background
+
+.box b1 fill=green width=100 height=100
+.box b2 fill=cyan width=100 height=100
+.box b3 fill=blue width=100 height=100
+.sprite s1
+ .put b1
+ .put b2 x=25 y=25
+ .put b3 x=50 y=50
+.end
+.sprite s2
+ .put b1
+ .put b2 x=25 y=25
+ .put b3 x=50 y=50
+.end
+
+.put s1 alpha=50%
+.put s2 alpha=50% x=300 blend=layer
+
+.end
+</code>
+
+</chapter>
+
+<chapter title="Filters">
+
+<p>
+An especially nice new feature of Flash 8 are filters.
+</p>
+<p>
+The current version of swfc supports the following filters:
+</p>
+
+<shell>
+dropshadow
+blur
+gradientglow
+bevel
+</shell>
+
+<section><title>The "dropshadow" filter</title>
+
+<c>dropsshadow</c> can be used to add shadows below (or above) flash
+objects.
+Every shadow has a color, and a direction/distance parameter (<c>angle</c>,<c>distance</c>),
+which controls where the shadow will be placed.
+The shadow is calculated by blurring (radios <c>blur</c> the alpha layer of the corresponding object,
+strengthening it (multiplication with <c>strength</c>), filling it with <c>color</c>
+and then merging it with the background.
+If the optional <c>knockout</c> option is given, the original object is removed, only the shadow
+is visible. If the <c>innershadow</c> parameter is given, the shadow will be <b>inside</b> the
+object.
+
+<code lang="swfc">
+.flash filename="shadow.swf" version=8 bbox=430x140 background=blue
+ .font myfont "Times.ttf"
+ .text mytext text="SHADOW" font=myfont size=140% color=yellow
+ .dropshadow myshadow color=black blur=5 angle=45 distance=50 passes=2 strength=1
+ .put mytext filter=myshadow y=75
+.end
+</code>
+
+</section>
+<section><title>The "bevel" filter</title>
+
+<p>
+The <c>bevel</c> filter essentially applies two shadows at once, at opposite directions.
+It supports the same arguments as the <c>dropshadow</c> filter, and also the optional
+<c>ontop</c> argument, which, if given, moves the "shadows" above the image. (useful
+together with <c>knockout</c>).
+</p>
+
+The following example demonstrates another feature of the swfc filter implementation: filters
+can also be animated.
+
+<code lang="swfc">
+.flash filename="bevel.swf" version=8 background=blue fps=12
+ .font arial "Arial.ttf"
+ .text abc text="FILTERS" font=arial size=130% color=red
+ .text beveltxt text="BEVEL" font=arial size=130% color=red
+
+ .bevel bevel0 highlight=white shadow=black blur=9 angle=45 distance=4 passes=2 strength=2 knockout
+ .bevel bevel1 highlight=white shadow=black blur=14 angle=45 distance=6 passes=2 strength=2 knockout
+
+ .bevel bevel2 highlight=white shadow=black blur=7 angle=0 distance=6 passes=2 strength=1 innershadow knockout
+ .bevel bevel3 highlight=white shadow=black blur=7 angle=360 distance=6 passes=2 strength=1 innershadow knockout
+
+ .put beveltxt filter=bevel0
+ .put abc filter=bevel2 y=80
+ .frame 50
+ .change beveltxt filter=bevel1
+ .frame 100
+ .change beveltxt filter=bevel0
+ .change abc filter=bevel3
+.end
+</code>
+
+</section>
+<section><title>The "blur" filter</title>
+
+The <c>blur</c> filter is probably the most simple filter- it only
+takes a blur radius and a number of passes. It then performs a blur effect
+by smoothening an area of <c>blurx</c> times <c>blury</c> pixels.
+
+<code lang="swfc">
+.flash filename="blur.swf" version=8 fps=50 bbox=200x200
+ .font arial "Arial.ttf"
+ .blur myblur1 blur=100 passes=2 # blur=100 is an abbreviation for blurx=100 blury=100
+ .blur myblur2 blurx=0 blury=0 passes=2
+ .blur myblur3 blurx=0 blury=100 passes=2
+ .textshape abc text="BLUR" font=arial size=100%
+ .filled fabc outline=abc line=2 color=blue fill=white
+ .filled fabc2 outline=abc line=2 color=red fill=yellow
+ .sprite mysprite
+ .put fabc pin=center x=100 y=100
+ .put fabc2 pin=center x=100 y=100
+ .frame 200
+ .change fabc pin=center rotate=360
+ .change fabc2 pin=center rotate=-360
+ .end
+ .put mysprite filter=myblur1
+ .frame 200
+ .change mysprite filter=myblur2
+ .frame 400
+ .change mysprite filter=myblur3
+.end
+</code>
+
+</section>
+<section><title>The "gradientglow" filter</title>
+
+<c>gradientglow</c> is like the <c>shadow filter</c>, only that the
+resulting shadow color is calculated from a gradient instead of a single color.
+
+<code lang="swfc">
+.flash filename="filters.swf" version=8
+ .font times "Times.ttf"
+ .text abc text="Gradientglow" font=times size=100% color=blue
+ .gradient fire:
+ 0% black/00
+ 25% red/40
+ 50% orange/80
+ 75% yellow/c0
+ 100% white/ff
+ .end
+ .gradientglow fireglow1 gradient=fire blur=20 innershadow angle=1 distance=20
+ .gradientglow fireglow2 gradient=fire blur=20 angle=0 distance=2 passes=1 knockout
+ .gradientglow fireglow3 gradient=fire blur=20 angle=0 distance=2 passes=1 ontop
+
+ .put abc1=abc filter=fireglow1
+ .put abc2=abc y=50 filter=fireglow2
+ .put abc3=abc y=100 filter=fireglow3
+.end
+
+</code>
+
+</section>
+
+</chapter>
+
</guide>
git.asbjorn.biz / swftools.git / blobdiff