quiethost

quiethost/progress_bar.sh

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+#!/bin/bash
+
+# Usage:
+# Source this script
+# enable_trapping <- optional to clean up properly if user presses ctrl-c
+# setup_scroll_area <- create empty progress bar
+# draw_progress_bar 10 <- advance progress bar
+# draw_progress_bar 40 <- advance progress bar
+# block_progress_bar 45 <- turns the progress bar yellow to indicate some action is requested from the user
+# draw_progress_bar 90 <- advance progress bar
+# destroy_scroll_area <- remove progress bar
+
+
+# Constants
+CODE_SAVE_CURSOR="\033[s"
+CODE_RESTORE_CURSOR="\033[u"
+CODE_CURSOR_IN_SCROLL_AREA="\033[1A"
+COLOR_FG="\e[30m"
+COLOR_BG="\e[42m"
+COLOR_BG_BLOCKED="\e[43m"
+RESTORE_FG="\e[39m"
+RESTORE_BG="\e[49m"
+
+# Variables
+PROGRESS_BLOCKED="false"
+TRAPPING_ENABLED="false"
+TRAP_SET="false"
+
+setup_scroll_area() {
+    # If trapping is enabled, we will want to activate it whenever we setup the scroll area and remove it when we break the scroll area
+    if [ "$TRAPPING_ENABLED" = "true" ]; then
+        trap_on_interrupt
+    fi
+
+    lines=$(tput lines)
+    let lines=$lines-1
+    # Scroll down a bit to avoid visual glitch when the screen area shrinks by one row
+    echo -en "\n"
+
+    # Save cursor
+    echo -en "$CODE_SAVE_CURSOR"
+    # Set scroll region (this will place the cursor in the top left)
+    echo -en "\033[0;${lines}r"
+
+    # Restore cursor but ensure its inside the scrolling area
+    echo -en "$CODE_RESTORE_CURSOR"
+    echo -en "$CODE_CURSOR_IN_SCROLL_AREA"
+
+    # Start empty progress bar
+    draw_progress_bar 0
+}
+
+destroy_scroll_area() {
+    lines=$(tput lines)
+    # Save cursor
+    echo -en "$CODE_SAVE_CURSOR"
+    # Set scroll region (this will place the cursor in the top left)
+    echo -en "\033[0;${lines}r"
+
+    # Restore cursor but ensure its inside the scrolling area
+    echo -en "$CODE_RESTORE_CURSOR"
+    echo -en "$CODE_CURSOR_IN_SCROLL_AREA"
+
+    # We are done so clear the scroll bar
+    clear_progress_bar
+
+    # Scroll down a bit to avoid visual glitch when the screen area grows by one row
+    echo -en "\n\n"
+
+    # Once the scroll area is cleared, we want to remove any trap previously set. Otherwise, ctrl+c will exit our shell
+    if [ "$TRAP_SET" = "true" ]; then
+        trap - INT
+    fi
+}
+
+draw_progress_bar() {
+    percentage=$1
+    lines=$(tput lines)
+    let lines=$lines
+    # Save cursor
+    echo -en "$CODE_SAVE_CURSOR"
+
+    # Move cursor position to last row
+    echo -en "\033[${lines};0f"
+
+    # Clear progress bar
+    tput el
+
+    # Draw progress bar
+    PROGRESS_BLOCKED="false"
+    print_bar_text $percentage
+
+    # Restore cursor position
+    echo -en "$CODE_RESTORE_CURSOR"
+}
+
+block_progress_bar() {
+    percentage=$1
+    lines=$(tput lines)
+    let lines=$lines
+    # Save cursor
+    echo -en "$CODE_SAVE_CURSOR"
+
+    # Move cursor position to last row
+    echo -en "\033[${lines};0f"
+
+    # Clear progress bar
+    tput el
+
+    # Draw progress bar
+    PROGRESS_BLOCKED="true"
+    print_bar_text $percentage
+
+    # Restore cursor position
+    echo -en "$CODE_RESTORE_CURSOR"
+}
+
+clear_progress_bar() {
+    lines=$(tput lines)
+    let lines=$lines
+    # Save cursor
+    echo -en "$CODE_SAVE_CURSOR"
+
+    # Move cursor position to last row
+    echo -en "\033[${lines};0f"
+
+    # clear progress bar
+    tput el
+
+    # Restore cursor position
+    echo -en "$CODE_RESTORE_CURSOR"
+}
+
+print_bar_text() {
+    local percentage=$1
+    local cols=$(tput cols)
+    let bar_size=$cols-17
+
+    local color="${COLOR_FG}${COLOR_BG}"
+    if [ "$PROGRESS_BLOCKED" = "true" ]; then
+        color="${COLOR_FG}${COLOR_BG_BLOCKED}"
+    fi
+
+    # Prepare progress bar
+    let complete_size=($bar_size*$percentage)/100
+    let remainder_size=$bar_size-$complete_size
+    progress_bar=$(echo -ne "["; echo -en "${color}"; printf_new "#" $complete_size; echo -en "${RESTORE_FG}${RESTORE_BG}"; printf_new "." $remainder_size; echo -ne "]");
+
+    # Print progress bar
+    echo -ne " Progress ${percentage}% ${progress_bar}"
+}
+
+enable_trapping() {
+    TRAPPING_ENABLED="true"
+}
+
+trap_on_interrupt() {
+    # If this function is called, we setup an interrupt handler to cleanup the progress bar
+    TRAP_SET="true"
+    trap cleanup_on_interrupt INT
+}
+
+cleanup_on_interrupt() {
+    destroy_scroll_area
+    exit
+}
+
+printf_new() {
+    str=$1
+    num=$2
+    v=$(printf "%-${num}s" "$str")
+    echo -ne "${v// /$str}"
+}