player

struct swf_definefont2 {
	swf_tag			f_tag;		/* 48 or 75 */
	unsigned short		f_font2_id;
	unsigned		f_font2_has_layout : 1;
	if(version >= 6) {
		unsigned	f_font2_reserved : 1;
		if(version >= 7) {
			unsigned	f_font2_small_text : 1;
		}
		unsigned	f_font2_reserved : 1;
	}
	else {
		unsigned	f_font2_shiftjis : 1;
		unsigned	f_font2_unicode : 1;
		unsigned	f_font2_ansii : 1;
	}
	unsigned		f_font2_wide_offsets : 1;
	unsigned		f_font2_wide : 1;	/* always 1 in v6.x+ */
	unsigned		f_font2_italic : 1;
	unsigned		f_font2_bold : 1;
	if(version >= 6) {
		unsigned char	f_font2_language;
	}
	else {
		unsigned char	f_font2_reserved;
	}
	unsigned char		f_font2_name_length;
	unsigned char		f_font2_name[f_font2_name_length];
	unsigned short		f_font2_glyphs_count;
	if(f_font2_wide_offsets) {
		unsigned long		f_font2_offsets[f_font2_glyphs_count];
		unsigned long		f_font2_map_offset;
	}
	else {
		unsigned short		f_font2_offsets[f_font2_glyphs_count];
		unsigned short		f_font2_map_offset;
	}
	swf_shape		f_font2_shapes[f_font2_glyphs_count];
	if(f_font_info_wide) {
		unsigned short		f_font2_map[f_font2_glyphs_count];
	}
	else {
		unsigned char		f_font2_map[f_font2_glyphs_count];
	}
	if(f_font2_has_layout) {
		signed short		f_font2_ascent;
		signed short		f_font2_descent;
		signed short		f_font2_leading_height;
		signed short		f_font2_advance[f_font2_glyphs_count];
		swf_rect		f_font2_bounds[f_font2_glyphs_count];
		signed short		f_font2_kerning_count;
		swf_kerning		f_font2_kerning[f_font2_kerning_count];
	}
};
/* DefineFont3 is the same as DefineFont2 */
typedef struct swf_definefont2 swf_definefont3;

It is common to use the DefineFont2 tag in order to create an array of shapes later re-used to draw strings of text on the screen. This tag must be used whenever a DefineEditText references a font; and in that case it is suggested you include a full description of the font with layouts.

The array of glyphs must be ordered in ascending order (the smaller glyph number saved first; thus 'a' must be saved before 'b', etc.).

All the characters should be defined in a 1024x1024 square (in pixels) to be drawn with the best possible quality. This square is called the EM square.

The ...

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 ...

The SWF Reference by Alexis is part of the free SSWF project.

This documentation is intended for people who want to program a Flash player, editor, or some similar tool handling Flash data.

The project comes with a complete C++ library that is designed to greatly simplify the generation and loading of Flash files.

The most common and simple geometric information are the object coordinates on the output screen. These are defined in TWIPs. There are 20 twips per pixels. Note that an embedded SWF file can be enlarged and/or reduced thus changing this basic scaling factor. To have exactly 20 twips per pixel you must ensure that the EMBED and/or OBJECT tags use a WIDTH and HEIGHT with exactly the same value as in the rectangle defined in the SWF header file divided by 20.

/* 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.

... Value Name Version 0 Drop Shadow 8

struct swf_gradient {
	if(tag == DefineShape4) {
		unsigned		f_spread_mode : 2;
		unsigned		f_interpolation_mode : 2;
		unsigned		f_count : 4;
	}
	else {
		unsigned		f_pad : 4;
		unsigned		f_count : 4;
	}
	swf_gradient_record	f_gradient_record[f_count];
	/* f_type is defined in the swf_fill_style encompassing this gradient */
	if(f_type == 0x13) {
		signed short fixed	f_focal_point;
	}
};

This structure defines a gradient. This is a set of colors which are used to define an image with colors smoothly varying from one color to the next. The gradient can be radial (circular) or linear (rectangular).

The f_count field is limited depending on the tag used and the version of SWF as defined below:

struct swf_line_style {
	if(f_tag == DefineMorphShape) {
		unsigned short twips	f_width;
		unsigned short twips	f_width_morph;
		swf_rgba		f_rgba;
		swf_rgba		f_rgba_morph;
	}
	else if(f_tag == DefineShape4 || f_tag == DefineMorphShape2) {
		unsigned short twips	f_width;
		if(f_tag == DefineMorphShape2) {
			unsigned short twips	f_width_morph;
		}
		unsigned		f_start_cap_style : 2;
		unsigned		f_join_style : 2;
		unsigned		f_has_fill : 1;
		unsigned		f_no_hscale : 1;
		unsigned		f_no_vscale : 1;
		unsigned		f_pixel_hinting : 1;
		unsigned		f_reserved : 5;
		unsigned		f_no_close : 1;
		unsigned		f_end_cap_style : 2;
		if(f_join_style == 2) {
			unsigned short fixed	f_miter_limit_factor;
		}
		if(f_has_fill) {
			swf_fill_style		f_fill_style;
		}
		else {
			swf_rgba		f_rgba;
			if(f_tag == DefineMorphShape2) {
				swf_rgba		f_rgba_morph;
			}
		}
	}
	else if(f_tag == DefineShape3) {
		unsigned short twips	f_width;
		swf_rgba		f_rgba;
	}
	else {
		unsigned short twips	f_width;
		swf_rgb				f_rgb;
	}
};

The width of the line is in TWIPS (1/20th of a pixel).

The f_start_cap_style and f_end_cap_style can be:

• 0 - Round cap,
• 1 - No cap,
• 2 - Square cap.

Round is the default, the way line caps looked before version 8. No Cap means that nothing is added at the tip of the line. This means the line stops exactly where you say it should end. The Square Cap is like the No Cap, but it has the cap which is about Width / 2.

The f_join_style can be:

/* f_type = 0x00 - solid fill */
struct swf_fill_style_solid {
	unsigned char		f_type;
	if(f_tag == DefineMorphShape || f_tag == DefineMorphShape2) {
		swf_rgba	f_rgba;
		swf_rgba	f_rgba_morph;
	}
	else if(f_tag == DefineShape3) {
		swf_rgba	f_rgba;
	}
	else {
		swf_rgb		f_rgb;
	}
};

/* f_type = 0x10 - linear gradient fill,
	    0x12 - radial gradient fill
	    0x13 - focal gradient fill (V8.0) */
struct swf_fill_style_gradient {
	unsigned char		f_type;
	swf_matrix			f_gradient_matrix;
	if(f_tag == DefineMorphShape || f_tag == DefineMorphShape2) {
		swf_matrix	f_gradient_matrix_morph;
	}
	swf_gradient		f_gradient;
};

/* f_type = 0x40 - tilled bitmap fill with smoothed edges,
	    0x41 - clipped bitmap fill with smoothed edges,
	    0x42 - tilled bitmap fill with hard edges (V7.0),
	    0x43 - clipped bitmap fill with hard edges (V7.0) */
struct swf_fill_style_bitmap {
	unsigned char		f_type;
	unsigned short		f_bitmap_ref;
	swf_matrix		f_bitmap_matrix;
	if(f_tag == DefineMorphShape || f_tag == DefineMorphShape2) {
		swf_matrix	f_bitmap_matrix_morph;
	}
};

union swf_fill_style {
	unsigned char		f_type;
	swf_fill_style_solid	f_solid;
	swf_fill_style_gradient	f_gradient;
	swf_fill_style_bitmap	f_bitmap;
};

The fill style is defined in the first byte. The values are defined below. Depending on that value, the fill style structure changes as shown below. swf_fill_style is a union of all the other structures.

Notice that types 0x42 and 0x43 are only available since version 7 and type 0x13 is only available since version 8.

Note that these values were introduced in Flash 7 but it looks like only player 8 supported the distinction between hard edges and smooth edges on a per shape basis. That would explain why I could not see any difference between smooth and hard shapes when I tested this feature ...

struct swf_placeobject2 {	/* and swf_placeobject3 */
	swf_tag			f_tag;		/* 26 or 70 */
	/* NOTE: the following flags can be read as one or two bytes also */
	if(version >= 8) {
		unsigned	f_place_reserved : 5;
		unsigned	f_place_bitmap_caching : 1;
		unsigned	f_place_blend_mode : 1;
		unsigned	f_place_filters : 1;
	}
	if(version >= 5) {
		unsigned	f_place_has_actions : 1;
	}
	else {
		unsigned	f_place_reserved : 1;
	}
	unsigned		f_place_has_clipping_depth : 1;
	unsigned		f_place_has_name : 1;
	unsigned		f_place_has_morph_position : 1;
	unsigned		f_place_has_color_transform : 1;
	unsigned		f_place_has_matrix : 1;
	unsigned		f_place_has_id_ref : 1;
	unsigned		f_place_has_move : 1;
	unsigned short		f_depth;
	if(f_place_has_id_ref) {
		unsigned short		f_object_id_ref;
	}
	if(f_place_has_matrix) {
		swf_matrix		f_matrix;
	}
	if(f_place_has_color_transform) {
		swf_color_transform	f_color_transform;
	}
	if(f_place_has_morph_position) {
		unsigned short		f_morph_position;
	}
	if(f_place_has_name) {
		string			f_name;
	}
	if(f_place_has_clipping_depth) {
		unsigned short		f_clipping_depth;
	}
	/* 3 next entries since v8.0 */
	if(f_place_filters) {
		unsigned char		f_filter_count;
		swf_any_filter		f_filter;
	}
	if(f_place_blend_mode) {
		unsigned char		f_blend_mode;
	}
	if(f_place_bitmap_caching) {
		/* WARNING: this is not defined in the Macromedia documentation
		 * it may be that it was part of the blend mode whenever the person
		 * who defined this byte was testing (I copied that from somewhere else!).
		 */
		unsigned char		f_bitmap_caching;
	}
	/* since v5.0 */
	if(f_place_has_actions) {
		unsigned short		f_reserved;
		if(version >= 6) {
			unsigned long	f_all_flags;
		}
		else {
			unsigned short	f_all_flags;
		}
		swf_event		f_event[<variable>];
		if(version >= 6) {
			unsigned long	f_end;	/* always zero */
		}
		else {
			unsigned short	f_end;	/* always zero */
		}
	}
};

This tag will be used to specify where and how to place an object in the next frame. The PlaceObject is much different and is presented separately.

The f_depth field is used to indicate at which depth the character is inserted in the current frame. There can be only one object per depth value (thus a maximum of 65536 objects can appear on a single frame).

The f_place_has_move and f_place_has_id_ref flags are used to indicate what to do at the given depth. The following table presents what happens depending on the current value.

f_place_has_move	...

struct swf_definesound {
	swf_tag			f_tag;		/* 14 */
	unsigned short		f_sound_id;
	unsigned		f_sound_format : 4;
	unsigned		f_sound_rate : 2;
	unsigned		f_sound_is_16bits : 1;
	unsigned		f_sound_is_stereo : 1;
	unsigned long		f_sound_samples_count;
	unsigned char		f_sound_data[<variable size>];
};

A DefineSound tag declares a set of samples of a sound effect or a music.

The sound samples can be compressed or not, stereo or not and 8 or 16 bits. The different modes are not all available in version 2, although the same tag is used in newer versions with additional capabilities.

The f_sound_is_16bits is always set to 1 (16bits samples) if the samples are compressed (neither Rawnor Uncompressed).

The f_sound_rate represents the rate at which the samples are defined. The rate at which it will be played on the target computers may differ. The following equation can be used to determine the ...