README.md

   1 ## Description
   2
   3 *bspwm* is a tiling window manager that represents windows as the leaves of a full binary tree.
   4
   5 It only responds to X events, and the messages it receives on a dedicated socket.
   6
   7 *bspc* is a program that writes messages on *bspwm*'s socket.
   8
   9 *bspwm* doesn't handle any keyboard or pointer inputs: a third party program (e.g. *sxhkd*) is needed in order to translate keyboard and pointer events to *bspc* invocations.
  10
  11 The outlined architecture is the following:
  12
  13 ```
  14         PROCESS          SOCKET
  15 sxhkd  -------->  bspc  <------>  bspwm
  16 ```
  17
  18 ## Configuration
  19
  20 The default configuration file is `$XDG_CONFIG_HOME/bspwm/bspwmrc`: this is simply a shell script that calls *bspc*.
  21
  22 Keyboard and pointer bindings are defined with [sxhkd](https://github.com/baskerville/sxhkd).
  23
  24 Example configuration files can be found in the [examples](examples) directory.
  25
  26 ## Monitors, desktops and windows
  27
  28 *bspwm* holds a list of monitors.
  29
  30 A monitor is just a rectangle that contains desktops.
  31
  32 A desktop is just a pointer to a tree.
  33
  34 Monitors only show the tree of one desktop at a time (their focused desktop).
  35
  36 The tree is a partition of a monitor's rectangle into smaller rectangular regions.
  37
  38 Each node in a tree either has zero or two children.
  39
  40 Each internal node is responsible for splitting a rectangle in half.
  41
  42 A split is defined by two parameters: the type (horizontal or vertical) and the ratio (a real number *r* such that *0 < r < 1*).
  43
  44 Each leaf node holds exactly one window.
  45
  46 ## Insertion Modes
  47
  48 ### Prelude
  49
  50 When *bspwm* receives a new window, it inserts it into a window tree at the specified insertion point (a leaf) using the insertion mode specified for that insertion point.
  51
  52 The insertion mode tells *bspwm* how it should alter the tree in order to insert new windows on a given insertion point.
  53
  54 By default the insertion point is the focused window and its insertion mode is *automatic*.
  55
  56 ### Manual Mode
  57
  58 The user can specify a region in the insertion point where the next new window should appear by sending a *node -p|--presel-dir DIR* message to *bspwm*.
  59
  60 The *DIR* argument allows to specify how the insertion point should be split (horizontally or vertically) and if the new window should be the first or the second child of the new internal node (the insertion point will become its *brother*).
  61
  62 After doing so the insertion point goes into *manual* mode.
  63
  64 Let's consider the following scenario:
  65
  66 ```
  67             a                          a                          a
  68            / \                        / \                        / \
  69           1   b         --->         c   b         --->         c   b
  70           ^  / \                    / \ / \                    / \ / \
  71             2   3                  4  1 2  3                  d  1 2  3
  72                                    ^                         / \
  73                                                             5   4
  74                                                             ^
  75
  76 +-----------------------+  +-----------------------+  +-----------------------+
  77 |           |           |  |           |           |  |     |     |           |
  78 |           |     2     |  |     4     |     2     |  |  5  |  4  |     2     |
  79 |           |           |  |     ^     |           |  |  ^  |     |           |
  80 |     1     |-----------|  |-----------|-----------|  |-----------|-----------|
  81 |     ^     |           |  |           |           |  |           |           |
  82 |           |     3     |  |     1     |     3     |  |     1     |     3     |
  83 |           |           |  |           |           |  |           |           |
  84 +-----------------------+  +-----------------------+  +-----------------------+
  85
  86             X                          Y                          Z
  87 ```
  88
  89 In state *X*, the insertion point is *1*.
  90
  91 We send the following message to *bspwm*: *node -p north*.
  92
  93 Then add a new window: *4*, this leads to state *Y*: the new internal node, *c* becomes *a*'s first child.
  94
  95 Finally we send another message: *node -p west* and add window *5*.
  96
  97 The ratio of the preselection (that ends up being the ratio of the split of the new internal node) can be changed with the *node -o|--presel-ratio* message.
  98
  99 ### Automatic Mode
 100
 101 The *automatic* mode, as opposed to the *manual* mode, doesn't require any user choice. The way the new window is inserted is determined by the value of the automatic scheme and the initial polarity settings.
 102
 103 #### Longest side
 104
 105 When the value of the automatic scheme is `longest_side`, the window will be attached as if the insertion point was in manual mode and the split direction was choosen based on the dimensions of the tiling rectangle and the initial polarity.
 106
 107 Let's consider the following scenario, where the initial polarity is set to `second_child`:
 108
 109 ```
 110              1                          a                          a
 111              ^                         / \                        / \
 112                          --->         1   2         --->         1   b
 113                                           ^                         / \
 114                                                                    2   3
 115                                                                        ^
 116
 117  +-----------------------+  +-----------------------+  +-----------------------+
 118  |                       |  |           |           |  |           |           |
 119  |                       |  |           |           |  |           |     2     |
 120  |                       |  |           |           |  |           |           |
 121  |           1           |  |     1     |     2     |  |     1     |-----------|
 122  |           ^           |  |           |     ^     |  |           |           |
 123  |                       |  |           |           |  |           |     3     |
 124  |                       |  |           |           |  |           |     ^     |
 125  +-----------------------+  +-----------------------+  +-----------------------+
 126
 127              X                          Y                          Z
 128 ```
 129
 130 In state *X*, a new window is added.
 131
 132 Since *1* is wide, it gets split vertically and *2* is added as *a*'s second child given the initial polarity.
 133
 134 This leads to *Y* where we insert window *3*. *2* is tall and is therefore split horizontally. *3* is once again added as *b*'s second child.
 135
 136 #### Spiral
 137
 138 When the value of the automatic scheme is `spiral`, the window will *take the space* of the insertion point.
 139
 140 Let's dive into the details with the following scenario:
 141
 142 ```
 143              a                          a                          a
 144             / \                        / \                        / \
 145            1   b         --->         1   c         --->         1   d
 146               / \                        / \                        / \
 147              2   3                      4   b                      5   c
 148              ^                          ^  / \                     ^  / \
 149                                           3   2                      b   4
 150                                                                     / \
 151                                                                    3   2
 152
 153  +-----------------------+  +-----------------------+  +-----------------------+
 154  |           |           |  |           |           |  |           |           |
 155  |           |     2     |  |           |     4     |  |           |     5     |
 156  |           |     ^     |  |           |     ^     |  |           |     ^     |
 157  |     1     |-----------|  |     1     |-----------|  |     1     |-----------|
 158  |           |           |  |           |     |     |  |           |  3  |     |
 159  |           |     3     |  |           |  3  |  2  |  |           |-----|  4  |
 160  |           |           |  |           |     |     |  |           |  2  |     |
 161  +-----------------------+  +-----------------------+  +-----------------------+
 162
 163              X                          Y                          Z
 164 ```
 165
 166 In state *X*, the insertion point, *2* is in automatic mode.
 167
 168 When we add a new window, *4*, the whole tree rooted at *b* is reattached, as the second child of a new internal node, *c*.
 169
 170 The splitting parameters of *b* (type: *horizontal*, ratio: *½*) are copied to *c* and *b* is rotated by 90° clockwise.
 171
 172 The tiling rectangle of *4* in state *Y* is equal to the tiling rectangle of *2* in state *X*.
 173
 174 Then the insertion of *5*, with *4* as insertion point, leads to *Z*.
 175
 176 The *spiral* automatic scheme generates window spirals that rotate clockwise (resp. anti-clockwise) if the insertion point is the first (resp. second) child of its parent.
 177
 178
 179 ## Supported protocols and standards
 180
 181 - The RandR and Xinerama protocols.
 182 - A subset of the EWMH and ICCCM standards.