Plymouth 交互

就俩基本对象: Image 和 Sprite

Plymouth Images

To create a new image you need to supply the filename of the image within the theme image directory to Image, e.g.

box_image = Image ("box.png");
logo_image = Image ("special://logo");   # "special://logo" is a special keyword which finds the logo image

You can also create images from text. These are useful to show text messages, e.g.

warning_image = Image.Text ("System running FSCK. This may take some time");

The default is white text color, but you can supply additional parameters of: red, green, blue, alpha, fontname and alignment. Default font is "Sans 12" and default alignment is "left". Alignement is only useful for multi-line text, and its possible values are "left", "center", or "right".

warning_image = Image.Text ("I feel faded", 0.8, 0.8, 0.8, 0.8, "Fixed");

The width and height of an image can be attained using GetWidth and GetHeight, e.g.

logo_area = logo_image.GetWidth() * logo_image.GetHeight();

An image can be rotated or scaled using Rotate and Scale, e.g.

upside_down_logo_image = logo_image.Rotate (3.1415); # the second paramiter is the angle in radians
fat_logo_image = logo_image.Scale (logo_image.GetWidth() * 2 , logo_image.GetHeight ()) # make the image twice the width

Plymouth Sprites

To place an image on the screen, we use sprites.

To create a new sprite call Sprite, then set the image using SetImage, e.g.

my_sprite = Sprite ();
my_sprite.SetImage (fat_logo_image);

You can also set the image while creating the sprite by supplying it to the constructor e.g.

my_sprite = Sprite (fat_logo_image);

The default placement of a new sprite is at the top left corner of the screen (at 0,0). To change the position call SetX and SetY, e.g.

my_sprite.SetX (100);
my_sprite.SetY (200);

If there are multiple sprites it us useful to decide which sprite should be shown above other. This is controlled using the Z component, the sprite with higher the Z is drawn on top.

background_sprite.SetZ (-10);
foreground_sprite.SetZ (10);

To set X, Y and Z in one call you can use SetPosition

logo_sprite.Setposition(100, 100, 0); # place at X=100, Y=100, Z=0

SetOpacity can make sprites transparent (the default opacity is solid 1) or even invisible when set to 0 , e.g.

faded_sprite.SetOpacity (0.5);
invisible_sprite.SetOpacity (0);

It is also possible to get the X/Y/Z/Opcaity/Image properties of a sprite.

sprite.SetOpacity(sprite.GetOpacity()/2);
sprite.SetPosition(sprite.GetX()+1, sprite.Gety()+1, sprite.GetZ());
sprite.SetImage(sprite.GetImage().Rotate(0.1));

Knowing the size of the window can be useful to position sprites. This can be reached using Window.GetWidth and Window.GetHeight, e.g.

centred_sprite.SetX (Window.GetWidth ()  / 2 - centred_sprite.GetImage().GetWidth()  / 2);
centred_sprite.SetY (Window.GetHeight () / 2 - centred_sprite.GetImage().GetHeight() / 2);

If the sprites do not fully cover the whole window, some of the sprite background will be exposed. To set the background colours use Window.SetBackground{Top,Bottom}Color. These take Red, Green and Blue values between 0 and 1, e.g.

Window.SetBackgroundTopColor (0, 0, 1);           # Nice blue on top of the screen fading to
Window.SetBackgroundBottomColor (0.8, 0.2, 0.1);  # an equally nice brown on the bottom

Plymouth Callbacks

Calling Plymouth.SetRefreshFunction with a function will set that function to be called up to 50 times every second, e.g.

fun refresh_callback ()
{
 time++;
}
Plymouth.SetRefreshFunction (refresh_callback);

Other callbacks which can be hooked onto are:

  • Plymouth.SetBootProgressFunction: the callback function is called with two numbers, time spent booting so far and the progress (between 0 and 1)
  • Plymouth.SetRootMountedFunction: the callback function is called when a new root is mounted
  • Plymouth.SetKeyboardInputFunction: the callback function is called with a string containing a new character entered on the keyboard
  • Plymouth.SetUpdateStatusFunction: the callback function is called with the new boot status string
  • Plymouth.SetDisplayPasswordFunction: the callback function is called when the display should display a password dialogue. First arg is prompt string, the second is the number of bullets.
  • Plymouth.SetDisplayQuestionFunction: the callback function is called when the display should display a question dialogue. First arg is prompt string, the second is the entry contents.
  • Plymouth.SetDisplayNormalFunction: the callback function is called when the display should return to normal
  • Plymouth.SetMessageFunction: the callback function is called when new message should be displayed. First arg is message to display. e.g.
fun progress_callback (time, progress)
{
 progress_status = "We have waited " + time + "seconds and we are "+ (progress * 100) + "% though";
 ...
}
Plymouth.SetBootProgressFunction (progress_callback);

To determine the mode of operation plymouth was started in use Plymouth.GetMode which returns a string of one of: "boot", "shutdown", "suspend", "resume" or unknown.

if (Plymouth.GetMode () == "suspend")
{
 ShowSuspendBackground();
}

Mathematics Functions

There are some basic mathematics functions to

  • Math.Abs: Absolute (positive) of a number
  • Math.Min: The smaller of two numbers
  • Math.Max: The greater of two numbers
  • Math.Clamp: Takes 3 numbers, value, min and max. Function forces the value to be between min and max, otherwise either min or max are returned.
  • Math.Pi: The value of Pi (3.14159...)
  • Math.Cos: Cosine function
  • Math.Sin: Sine function
  • Math.Tan: Tangent function
  • Math.ATan2: Arc tangent function taking 2 values (see "man atan2")
  • Math.Sqrt: Square root
  • Math.Int: Returns the rounded down integer.
  • Math.Random: Returns a pseudo random number between 0 and 1.

举个例子

while true; do  sudo plymouthd ; for i in `seq 1 100|sort -rn `; do sudo plyouth display-message --text="Bomb has been setting and startting $i" ; sudo plymouth --show-splash ; sleep 1; done ; sudo plymouth --quit ; done

效果如图： 01