pfetch: Revert to larger but more reliable print method. Closes #46

Author: dylanaraps

pfetch

@@ -3,6 +3,59 @@
 # pfetch - Simple POSIX sh fetch script.
 
 log() {
+    # The 'log()' function handles the printing of information.
+    # In 'pfetch' (and 'neofetch'!) the printing of the ascii art and info
+    # happen independently of each other.
+    #
+    # The size of the ascii art is stored and the ascii is printed first.
+    # Once the ascii is printed, the cursor is located right below the art
+    # (See marker $[1]).
+    #
+    # Using the stored ascii size, the cursor is then moved to marker $[2].
+    # This is simply a cursor up escape sequence using the "height" of the
+    # ascii art.
+    #
+    # 'log()' then moves the cursor to the right the "width" of the ascii art
+    # with an additional amount of padding to add a gap between the art and
+    # the information (See marker $[3]).
+    #
+    # When 'log()' has executed, the cursor is then located at marker $[4].
+    # When 'log()' is run a second time, the next line of information is
+    # printed, moving the cursor to marker $[5].
+    #
+    # Markers $[4] and $[5] repeat all the way down through the ascii art
+    # until there is no more information left to print.
+    #
+    # Every time 'log()' is called the script keeps track of how many lines
+    # were printed. When printing is complete the cursor is then manually
+    # placed below the information and the art according to the "heights"
+    # of both.
+    #
+    # The math is simple: move cursor down $((ascii_height - info_height)).
+    # If the aim is to move the cursor from marker $[5] to marker $[6],
+    # plus the ascii height is 8 while the info height is 2 it'd be a move
+    # of 6 lines downwards.
+    #
+    # However, if the information printed is "taller" (takes up more lines)
+    # than the ascii art, the cursor isn't moved at all!
+    #
+    # Once the cursor is at marker $[6], the script exits. This is the gist
+    # of how this "dynamic" printing and layout works.
+    #
+    # This method allows ascii art to be stored without markers for info
+    # and it allows for easy swapping of info order and amount.
+    #
+    # $[2] ___      $[3] goldie@KISS
+    # $[4](.· |     $[5] os KISS Linux
+    #     (<> |
+    #    / __  \
+    #   ( /  \ /|
+    #  _/\ __)/_)
+    #  \/-____\/
+    # $[1]
+    #
+    # $[6] /home/goldie $
+
     # End here if no data was found.
     [ "$2" ] || return
 
@@ -22,10 +75,27 @@ log() {
         info=$*
     }
 
-    # Construct the information string.
-    out="[3${PF_COL1-4};1m${name}"
-    out="$out${PF_SEP}[$((info_length-${#name}))C"
-    out="$out[3${PF_COL2-7}m$info"
+    # Move the cursor to the right, the width of the ascii art with an
+    # additional gap for text spacing.
+    printf '[%sC' "${ascii_width--1}"
+
+    # Print the info name and color the text.
+    printf '[3%s;1m%s' "${PF_COL1-4}" "$name"
+
+    # Print the info name and info data separator.
+    printf %s "$PF_SEP"
+
+    # Move the cursor backward the length of the *current* info name and
+    # then move it forwards the length of the *longest* info name. This
+    # aligns each info data line.
+    printf '[%sD[%sC' "${#name}" "${PF_ALIGN-$info_length}"
+
+    # Print the info data, color it and strip all leading whitespace
+    # from the string.
+    printf '[3%sm%s\n' "${PF_COL2-7}" "$info"
+
+    # Keep track of the number of times 'log()' has been run.
+    info_height=$((${info_height:-0} + 1))
 }
 
 get_title() {
@@ -42,7 +112,7 @@ get_title() {
     # shellcheck disable=SC2039
     hostname=${HOSTNAME:-${hostname:-$(hostname)}}
 
-    log "[3${PF_COL3:-1}m${user}${c7}@[3${PF_COL3:-1}m${hostname}" " "
+    log "[3${PF_COL3:-1}m${user}${c7}@[3${PF_COL3:-1}m${hostname}" " " >&6
 }
 
 get_os() {
@@ -53,7 +123,7 @@ get_os() {
     # On first run, this function displays _nothing_, only on the second
     # invocation is 'log()' called.
     [ "$distro" ] && {
-        log os "$distro"
+        log os "$distro" >&6
         return
     }
 
@@ -216,18 +286,13 @@ get_kernel() {
     case $os in
         # Don't print kernel output on some systems as the
         # OS name includes it.
-        *BSD*|Haiku|Minix) ;;
-
-        IRIX)
-            kernel=$(uname -vR)
-            kernel=${kernel#* }
+        *BSD*|Haiku|Minix) 
+            return 
         ;;
+    esac
 
-        *)
-            # '$kernel' is the cached output of 'uname -r'.
-            log kernel "$kernel"
-        ;;
-   esac
+    # '$kernel' is the cached output of 'uname -r'.
+    log kernel "$kernel" >&6
 }
 
 get_host() {
@@ -296,7 +361,7 @@ get_host() {
     done
 
     # '$arch' is the cached output from 'uname -m'.
-    log host "${host:-$arch}"
+    log host "${host:-$arch}" >&6
 }
 
 get_uptime() {
@@ -370,7 +435,7 @@ get_uptime() {
     [ "$h" = 0 ] || uptime="${uptime}${h}h "
     [ "$m" = 0 ] || uptime="${uptime}${m}m "
 
-    log uptime "${uptime:-0m}"
+    log uptime "${uptime:-0m}" >&6
 }
 
 get_pkgs() {
@@ -482,7 +547,7 @@ get_pkgs() {
         IRIX) packages=$((packages - 3)) ;;
     esac
 
-    [ "$packages" -gt 1 ] && log pkgs "$packages"
+    [ "$packages" -gt 1 ] && log pkgs "$packages" >&6
 }
 
 get_memory() {
@@ -685,7 +750,7 @@ get_memory() {
         ;;
     esac
 
-    log memory "${mem_used:-?}M / ${mem_full:-?}M"
+    log memory "${mem_used:-?}M / ${mem_full:-?}M" >&6
 }
 
 get_wm() {
@@ -814,7 +879,7 @@ get_wm() {
         ;;
     esac
 
-    log wm "$wm"
+    log wm "$wm" >&6
 }
 
 
@@ -825,18 +890,18 @@ get_de() {
     #
     # Display the value of '$XDG_CURRENT_DESKTOP', if it's empty,
     # display the value of '$DESKTOP_SESSION'.
-    log de "${XDG_CURRENT_DESKTOP:-$DESKTOP_SESSION}"
+    log de "${XDG_CURRENT_DESKTOP:-$DESKTOP_SESSION}" >&6
 }
 
 get_shell() {
     # Display the basename of the '$SHELL' environment variable.
-    log shell "${SHELL##*/}"
+    log shell "${SHELL##*/}" >&6
 }
 
 get_editor() {
     # Display the value of '$VISUAL', if it's empty, display the
     # value of '$EDITOR'.
-    log editor "${VISUAL:-$EDITOR}"
+    log editor "${VISUAL:-$EDITOR}" >&6
 }
 
 get_palette() {
@@ -850,8 +915,8 @@ get_palette() {
 
     # Print the palette with a new-line before and afterwards.
     printf '\n' >&6
-    log "$palette
-        " " "
+    log "$palette 
+        " " " >&6
 }
 
 get_ascii() {
@@ -1363,6 +1428,8 @@ get_ascii() {
     # information. The 'sed' is used to strip 'm' color codes from
     # the ascii art so they don't affect the width variable.
     while read -r line; do
+        ascii_height=$((${ascii_height:-0} + 1))
+
         # This was a ternary operation but they aren't supported in
         # Minix's shell.
         [ "${#line}" -gt "${ascii_width:-0}" ] &&
@@ -1378,6 +1445,13 @@ get_ascii() {
 
     # Add a gap between the ascii art and the information.
     ascii_width=$((ascii_width + 4))
+
+    # Print the ascii art and position the cursor back where we
+    # started prior to printing it.
+    # '[1m':   Print the ascii in bold.
+    # '[m':    Clear bold.
+    # '[%sA':  Move the cursor up '$ascii_height' amount of lines.
+    printf '%s[%sA' "$ascii" "$ascii_height" >&6
 }
 
 main() {
@@ -1444,10 +1518,6 @@ main() {
         set -f
         set +f ${PF_INFO-ascii title os host kernel uptime pkgs memory}
 
-        # Grab the ascii art if the user has enabled it. This simply
-        # populates the '$ascii' variable.
-        case $@ in *ascii*) get_ascii; shift; esac
-
         # Iterate over the info functions to determine the lengths of the
         # "info names" for output alignment. The option names and subtitles
         # match 1:1 so this is thankfully simple.
@@ -1463,22 +1533,26 @@ main() {
         # Add an additional space of length to act as a gap.
         info_length=$((info_length + 1))
 
-        while IFS= read -r line || [ "$1" ]; do
-            # Iterate over the info skipping any lines
-            # which are blank.
-            for info; do
-                "get_$1"
-                shift "$(($# ? 1 : 0))"
-                [ "$out" ] && break
-            done 
-
-            printf '\033[%sC%s\033[m\r\033[1m%s\033[m\n' \
-                "$ascii_width" "$out" "$line" >&6
-            out=
-        done <<-EOF
-			$ascii
-		EOF
+        # Iterate over the above list and run any existing "get_" functions.
+        for info; do "get_$info"; done
     }
+
+    # Position the cursor below both the ascii art and information lines
+    # according to the height of both. If the information exceeds the ascii
+    # art in height, don't touch the cursor (0/unset), else move it down
+    # N lines.
+    #
+    # This was a ternary operation but they aren't supported in Minix's shell.
+    [ "${info_height:-0}" -lt "${ascii_height:-0}" ] &&
+        cursor_pos=$((ascii_height - info_height))
+
+    # Print '$cursor_pos' amount of newlines to correctly position the
+    # cursor. This used to be a 'printf $(seq X X)' however 'seq' is only
+    # typically available (by default) on GNU based systems!
+    while [ "${i:=0}" -le "${cursor_pos:-0}" ]; do
+        printf '\n'
+        i=$((i + 1))
+    done >&6
 }
 
 main "$@"