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SWF Internal Functions

Since Flash version 5, you can use internal functions (really member functions or methods of internal objects.) These functions are always available. These methods are called using the Call Function action with the name of the object and function separated by a period. A few of these internal functions are duplicates of some direct action script instructions. In general, it is preferred to use these internal functions rather than the direct action. However, direct actions are a good way to optimize your ActionScript code.

Similarly, you can access internal constants (really variable ...

Equal (typed)

SWF Action
Action Category: 
Comparisons
Action Details: 
(typed)
Action Identifier: 
73
Action Structure: 
<n.a.>
Action Length: 
0 byte(s)
Action Stack: 
pop 2 (a), push 1 (b)
Action Operation: 
a1 := pop();
a2 := pop();
if(is_int(a1) && is_int(a2)) {
  i1 := (int)a1;
  i2 := (int)a2;
  r := i2 == i1;    // compare integers
}
else if(is_numeric(a1) && is_numeric(a2)) {
  f1 := (float)a1;
  f2 := (float)a2;
  r := f2 == f1;    // compare floating points, likely to always return false!
}
else {
  s1 := (string)a1;
  s2 := (string)a2;
  r := s2 == s1;    // compare characters, case sensitive
}
push(r);
Action Flash Version: 
5

Pop two integers, floats or strings, compute whether they are equal and push the Boolean result back on the stack.

The != operator can be simulated using the Logical Not action right after the Equal (typed).

If a mix set of types is popped from the stack, conventional conversions occur. Strings may be transformed to numbers and numbers to strings as with the untyped Equal operator.

And

SWF Action
Action Category: 
Logical and Bitwise
Action Details: 
0
Action Identifier: 
96
Action Structure: 
<n.a.>
Action Length: 
0 byte(s)
Action Stack: 
pop 2 (i), push 1 (i)
Action Operation: 
i1 := pop();
i2 := pop();
r := i2 & i1;
push(r);
Action Flash Version: 
5

Pop two integers, compute the bitwise AND, and push the result back on the stack.

CSMTextSettings

Tag Info
Tag Number: 
74
Tag Type: 
Define
Tag Flash Version: 
8
Brief Description: 

Define whether CSM text should be used in a previous DefineText, DefineText2 or DefineEditText.

Tag Structure: 
struct swf_csmtextsettings {
	swf_tag			f_tag;		/* 74 */
	unsigned short		f_text_id_ref;
	unsigned		f_use_flag_type : 2;
	unsigned		f_grid_fit : 3;
	unsigned		f_reserved : 3;
	long float		f_thickness;
	long float		f_sharpness;
	unsigned char		f_reserved;
};

The CSMTextSettings are used to change the rendering mode of glyphs in a DefineText, DefineText2 and DefineEditText.

The f_text_id_ref is a reference to a tag holding some texts which glyphs need to be tweaked with these settings.

The f_use_flag_type defines which of the system (0) or Flash (1) font renderer should be used.

Appendix B — History of the SSWF reference

Dec 2, 2009

Moved the monolithic documentation to a multi-page hierarchical document that includes everything we had before plus many links, many terms attached to all pages (tags, English words.) And revision of most of the text for better English and clarification in some places.

Strengthen the formatting with CCK fields so all declarations look alike.

Broken up the actions from one large table to a set of pages.

Dec 14, 2008

Started work on the Load() feature of the SSWF library. This helped fixing several small mistakes in the documentation.

May 18, 2008

Fixed the ...

Appendix A — The geometry in SWF — Edges

Edges are used to define a shape vector based and also coordinates where images need to be drawn. The edges are always coordinates from where ever your last point was to where ever you want the next point to be (a little like a turtle in LOGO).

Appendix A — The geometry in SWF — Matrix

The coordinates are often transformed with the use of a matrix. The matrix is similar to a transformation matrix in Postscript. It includes a set of scaling factors, rotation angles and translations.

When only the scaling factors are used (no rotation) then these are ratios as one would expect. If a rotation is also applied, then the scaling ratios will be affected accordingly.

SWF Any Filter (swf_any_filter)

SWF Structure Info
Tag Flash Version: 
8
SWF Structure: 
/* the filter type */
struct swf_filter_type {
	unsigned char	f_type;
};

struct swf_filter_glow {
	swf_filter_type	f_type;		/* 0, 2, 3, 4 or 7 */
	if(f_type == GradientGlow || f_type == GradientBevel) {
		unsigned char		f_count;
	}
	else {
		f_count = 1;
	}
	swf_rgba		f_rgba[f_count];
	if(f_type == Bevel) {
		swf_rgba		f_highlight_rgba[f_count];
	}
	if(f_type == GradientGlow || f_type == GradientBevel) {
		unsigned char		f_position[f_count];
	}
	signed long fixed	f_blur_horizontal;
	signed long fixed	f_blur_vertical;
	if(f_type != Glow) {
		signed long fixed	f_radian_angle;
		signed long fixed	f_distance;
	}
	signed short fixed	f_strength;
	unsigned		f_inner_shadow : 1;
	unsigned		f_knock_out : 1;
	unsigned		f_composite_source : 1;
	if(f_type == Bevel) {
		unsigned		f_on_top : 1;
	}
	else {
		unsigned		f_reserved : 1;
	}
	if(f_type == GradientGlow || f_type == GradientBevel) {
		unsigned		f_passes : 4;
	}
	else {
		unsigned		f_reserved : 4;
	}
};

struct swf_filter_blur {
	swf_filter_type		f_type;	/* 1 */
	unsigned long fixed	f_blur_horizontal;
	unsigned long fixed	f_blur_vertical;
	unsigned		f_passes : 5;
	unsigned		f_reserved : 3;
};

struct swf_filter_convolution {
	swf_filter_type	f_type;		/* 5 */
	unsigned char	f_columns;
	unsigned char	f_rows;
	long float	f_divisor;
	long float	f_bias;
	long float	f_weights[f_columns × f_rows];
	swf_rgba	f_default_color;
	unsigned	f_reserved : 6;
	unsigned	f_clamp : 1;
	unsigned	f_preserve_alpha : 1;
};

struct swf_filter_colormatrix {
	swf_filter_type	f_type;		/* 6 */
	long float	f_matrix[20];
};

struct swf_any_filter {
	swf_filter_type			f_fitler_type;
	swf_filter_blur			f_filter_blur;
	swf_filter_colormatrix		f_filter_colormatrix;
	swf_filter_convolution		f_filter_convolution;
	swf_filter_glow			f_filter_glow;
};

A filter defines how to transform the objects it is attached to. The first byte is the filter type. The data following depend on the type. Because each filter is much different, they are defined in separate structures. You can attach a filter to an object using an ActionScript or the PlaceObject3 tag.

The following describes the different filters available since version 8.

SWF RGBA (swf_rgba)

SWF Structure Info
Tag Flash Version: 
1
SWF Structure: 
struct swf_rgba {
	unsigned char		f_red;
	unsigned char		f_green;
	unsigned char		f_blue;
	unsigned char		f_alpha;1
};
  • 1. 0 represent a fully transparent color, 255 represents a solid color.

The color components can be set to any value from 0 (no intensity) to maximum intensity (255).1

  • 1. For some PNG images, the red, green and blue colors may need to be multiplied by their alpha channel value before saved. Use the following formula to compute the proper values:

       f_red = orginal red * f_alpha / 255

File Header

Tag Info
Tag Number: 
-1
Tag Type: 
Format
Tag Flash Version: 
1
Brief Description: 

Although it isn't a tag per say, we consider the file header as being a tag because it represents a block in the flash file. Since version 8, it can be complemented by the FileAttributes tag.

Tag Structure: 
struct swf_header {1
	unsigned char		f_magic[3];	/* 'FWS' or 'CWS' */
	unsigned char		f_version;
	unsigned long		f_file_length;
}

struct swf_header_movie {2
	swf_rect		f_frame_size;
	unsigned short fixed	f_frame_rate;
	unsigned short		f_frame_count;
};
  • 1. This part is never compressed
  • 2. Although considered part of the header, this part is compressed in the 'CWS' format.

The file header is found at the very beginning of the file. It should be used to determine whether a file is an SWF file or not. Also, it contains information about the frame size, the speed at which is should be played and the version (determining the tags and actions possibly used in the file).

The f_magic[3] array is defined as the characters: 'FWS' (it is going backward probably because it was supposed to be read in a little endian as a long word). A movie can be compressed when the version is set to 6 or more. In this case, the magic characters are: 'CWS'.

The f_version ...