NAME

blend_image - Change image opacity.

SYNOPSIS

nil
blend_image( VID or VIDtbl, opacity, time, interp )

DESCRIPTION

Changes the opacity of the selected VID s either immediately (default) or by setting an optional time argument to a non-negative integer. This function either accepts single VID s or a group of VID s in a table (iteration will follow the behavior of pairs() Interp can be set to one of the constants ( INTERP_LINEAR , INTERP_SINE , INTERP_EXPIN , INTERP_EXPOUT , INTERP_EXPINOUT , INTERP_SMOOTHSTEP ).

NOTES

1: VID s with an opacity other than 0.0 (hidden) and 1.0 (opaque, visible) will be blended.
2: Values outside the allowed range will be clamped.
3: The blend behavior is dictated by the default global blendfunc value (src_alpha, 1-src_alpha) and can be overridden with force_image_blend(mode)

EXAMPLE

function blend_image0()
      a = fill_surface(128, 128, 255, 0, 0);
      b = fill_surface(128, 128, 0, 255, 0);
      move_image(b, 64, 64);
      show_image({a,b});
      blend_image(b, 0.5, 100);
end

MISUSE

function blend_image0()
      a = fill_surface(128, 128, 255, 0, 0);
      b = fill_surface(128, 128, 0, 255, 0);
      move_image(b, 64, 64);
      show_image({a,b});
      blend_image(b, -0.5, -100);
end

MISUSE

function blend_image1()
      a = fill_surface(128, 128, 255, 0, 0);
      b = fill_surface(128, 128, 0, 255, 0);
      move_image(b, 64, 64);
      show_image({a,b});
      blend_image("a", 0.5, 100);
end

MISUSE

function blend_image2()
      a = fill_surface(128, 128, 255, 0, 0);
      b = fill_surface(128, 128, 0, 255, 0);
      move_image(b, 64, 64);
      show_image({a,b});
      blend_image({-1, "a", true, 5.0}, true, "error");
end