[Commits] [wesnoth/wesnoth] 284b9f: Cleaned up handling of basic alpha setting

[GitHub]

  Branch: refs/heads/surface_cleanup
  Home:   https://github.com/wesnoth/wesnoth
  Commit: 284b9fad897e6d47ac2c05f2a128d70e9bd1bb63
      https://github.com/wesnoth/wesnoth/commit/284b9fad897e6d47ac2c05f2a128d70e9bd1bb63
  Author: Charles Dang <exodia339 at gmail.com>
  Date:   2016-09-13 (Tue, 13 Sep 2016)

  Changed paths:
    M src/CMakeLists.txt
    M src/SConscript
    M src/about.cpp
    M src/attack_prediction_display.cpp
    M src/display.cpp
    M src/editor/action/mouse/mouse_action.cpp
    M src/editor/action/mouse/mouse_action_item.cpp
    M src/editor/action/mouse/mouse_action_map_label.cpp
    M src/editor/action/mouse/mouse_action_select.cpp
    M src/editor/action/mouse/mouse_action_unit.cpp
    M src/editor/action/mouse/mouse_action_village.cpp
    M src/editor/palette/tristate_button.cpp
    M src/floating_label.cpp
    M src/font.cpp
    M src/game_display.cpp
    M src/image_modifications.cpp
    R src/sdl/alpha.cpp
    R src/sdl/alpha.hpp
    M src/sdl/rect.cpp
    M src/sdl/utils.cpp
    M src/sdl/utils.hpp
    M src/widgets/textbox.cpp

  Log Message:
  -----------
  Cleaned up handling of basic alpha setting

This does a few things:
* Refactored adjust_surface_alpha to use SDL_SetSurfaceAlphaMod
* Made all uses of the legacy SDL_SetAlpha use adjust_surface_alpha
* Made adjust_surface_alpha now take a non-const reference and perform the operation on the surface directly.