libsswf: sswf::BlendMode Class Reference

The following lists the blend modes available when placing an object on your screen.

In the following, I included formulas which use the following variables:

• R - the resulting color
• C - the source color (i.e. the object in the TagPlace or State)
• B - the background (i.e. what has been drawn before this object)

Enumerator:

BLEND_MODE_UNDEFINED	According to Macromedia this is the same as sswf::BlendMode::BLEND_MODE_NORMAL. This value should probably not be used, yet according to the Macromedia documentation, it is equivalent to sswf::BlendMode::BLEND_MODE_NORMAL This is a do nothing blending mode. R = C
BLEND_MODE_NORMAL	A do nothing blending mode. This blending mode has no effect on the object being placed. Note: This may be a place holder in case you want to apply some blending mode with an ActionScript. Without it you may not be able to apply any blending mode from a script (TBD). R = C
BLEND_MODE_LAYER	Use multiple objects. This blending mode uses multiple objects to render the final output. At this time, it isn't clear to me what this does...
BLEND_MODE_MULTIPLY	Multiply the background and the object colors (light effect). This blending mode can be used to multiply the background colors with the object being placed. When the object being placed is a grey scale, this is a way to apply brightness to the background. Thus you can generate the effect of a light (or a reflection of a light) on the screen. R = B × C / 255
BLEND_MODE_SCREEN	Multiply the inverse of the background and the object colors. There is probably no good reason to use the inverse color of the object since the object could be rendered properly in the first place (i.e. if you need 255, use white and if you need 0 use black). Yet, this filter multiplies the inverse of the background and the object colors together. R = (255 - B) × (255 - C) / 255
BLEND_MODE_LIGHTEN	Use the largest of the two colors. Select which of the background or the object being placed has the largest component. Use black in your object to not affect the screen. R = max(B, C)
BLEND_MODE_DARKEN	Use the largest of the two colors. Select which of the background or the object being placed has the smallest component. Use white in your object to not affect the screen. R = min(B, C)
BLEND_MODE_DIFFERENCE	Take the absolute value of the object color minus the background color. At this time, I'm not too sure what this is for. The colors will loop around with this object and in general this make the image look weird. May be a good idea to create some sort of negative effect. R = | B - C |
BLEND_MODE_ADD	Add the object components to the background. This filter can be used for a strong brightness effect. Watchout, do not create too bright an object for this blend mode. It would otherwise make your screen look bad. R = max(B + C, 255)
BLEND_MODE_SUBTRACT	Subject the object components from the background. This filter can be used for a strong darkning effect. Watchout, do not create too bright an object for this blend mode. It would otherwise make your screen look bad. R = min(B - C, 0)
BLEND_MODE_INVERT	Inverse the background colors. This filter does not use the source image for anything more than know where to apply the filter. Otherwise it inverts the color creating a negative (the same as when you take pictures with your camera, the resulting film is a negative -- the colors are invered.) R = 255 - B
BLEND_MODE_ALPHA	Copy the object alpha in the background. This filter copies the alpha channel as is from the object to the background. Used in a Sprite, I suppose this can be used to switch between different alpha channels for the same object. Ra = Ca
BLEND_MODE_ERASE	Copy the inverse of the object alpha in the background. This filter copies the inverts of the alpha channel from the object to the background. This as the effect of making the object itself disappear... and what's around appear, I would think. Ra = 255 - Ca
BLEND_MODE_OVERLAY	Applies a MULTIPLY or SCREEN effect depending on the current background colors. This filter copies the alpha channel as is from the object to the background. R = (B < 128 ? B × C : (255 - B) × (255 - C)) / 255
BLEND_MODE_HARDLIGHT	Applies a MULTIPLY or SCREEN effect depending on the current background colors. This filter copies the alpha channel as is from the object to the background. R = (C < 128 ? B × C : (255 - B) × (255 - C)) / 255

The constructor initializes the blend mode to the default of: BLEND_MODE_UNDEFINED.

See also:

sswf::BlendMode::HasBlendMode(void) const

References BLEND_MODE_UNDEFINED, and f_blend_mode.

This function returns the current blending mode as set by SetBlendMode() or SetBlendModeByName().

Returns:

The current blend mode

See also:

sswf::BlendMode::SetBlendMode(blend_mode_t blend_mode)

sswf::BlendMode::SetBlendModeByName(const char *blend_mode_name)

References f_blend_mode.

This function determines whether a filter was defined in this BlendMode object.

This is the same as testing wheter the BlendMode::HasBlendMode(void) const function returns BLEND_MODE_UNDEFINED.

Returns:

true when the blend mode is not BLEND_MODE_UNDEFINED; false otherwise

See also:

sswf::BlendMode::SetBlendMode(blend_mode_t blend_mode)

sswf::BlendMode::SetBlendModeByName(const char *blend_mode_name)

References BLEND_MODE_UNDEFINED, and f_blend_mode.

Referenced by sswf::TagPlace::PreSave(), sswf::TagPlace::Save(), and sswf::State::Save().

This function reads the blend mode in the specified Data buffer.

Parameters:

[in]

data

The Data buffer where the blend mode is to be saved

Returns:

ERROR_CODE_NONE if no error occurs, an error code otherwise

References sswf::ErrorManager::ERROR_CODE_NONE, f_blend_mode, and sswf::Data::GetByte().

Referenced by sswf::State::Parse().

This function saves the specified blend mode in the specified Data buffer.

Parameters:

[in]

data

The Data buffer where the blend mode is to be saved

References f_blend_mode, and sswf::Data::PutByte().

Referenced by sswf::TagPlace::Save(), and sswf::State::Save().

This function defines the filter to use with a TagPlace or State object.

Note:

Trying to set a mode which does not exist forces the mode to BLEND_MODE_UNDEFINED.

Parameters:

[in]

blend_mode

The new blend mode (BLEND_MODE_...)

See also:

sswf::BlendMode::SetBlendModeName(const char *blend_mode_name)

References BLEND_MODE_ADD, BLEND_MODE_ALPHA, BLEND_MODE_DARKEN, BLEND_MODE_DIFFERENCE, BLEND_MODE_ERASE, BLEND_MODE_HARDLIGHT, BLEND_MODE_INVERT, BLEND_MODE_LAYER, BLEND_MODE_LIGHTEN, BLEND_MODE_MULTIPLY, BLEND_MODE_NORMAL, BLEND_MODE_OVERLAY, BLEND_MODE_SCREEN, BLEND_MODE_SUBTRACT, BLEND_MODE_UNDEFINED, and f_blend_mode.

This function is similar to the sswf::BlendMode::SetBlendMode(blend_mode_t blend_mode) except that it takes a name instead of a number to define the blending mode to use.

The supported names are the same as those found in the sswf::BlendMode::blend_mode_t enumeration without the "BLEND_MODE_" part and excluding UNDEFINED (you can reset the blend mode to Undefined by calling sswf::BlendMode::SetBlendMode(sswf::BlendMode::BLEND_MODE_UNDEFINED) instead.)

Parameters:

[in]

blend_mode_name

The ASCII name of the blend mode to use

Returns:

The new blend mode value or BLEND_MODE_UNDEFINED when the input name was not a valid blend mode

See also:

sswf::TagBase::SetBlendMode(blend_mode_t blend_mode)

References BLEND_MODE_ADD, BLEND_MODE_ALPHA, BLEND_MODE_DARKEN, BLEND_MODE_DIFFERENCE, BLEND_MODE_ERASE, BLEND_MODE_HARDLIGHT, BLEND_MODE_INVERT, BLEND_MODE_LAYER, BLEND_MODE_LIGHTEN, BLEND_MODE_MULTIPLY, BLEND_MODE_NORMAL, BLEND_MODE_OVERLAY, BLEND_MODE_SCREEN, BLEND_MODE_SUBTRACT, BLEND_MODE_UNDEFINED, and f_blend_mode.

Referenced by BlendMode(), GetBlendMode(), HasBlendMode(), Parse(), Save(), SetBlendMode(), and SetBlendModeByName().