From bed7cc14f9bd3b3169bcb8c122dc55ec31ff7e66 Mon Sep 17 00:00:00 2001
From: Rawiri Blundell <Rawiri.Blundell@radium.co.nz>
Date: Wed, 29 Oct 2025 13:39:19 +1300
Subject: [PATCH 1/5] gallery/noise: Initial commit

---
 gallery/noise/config.sh | 10 ++++++
 gallery/noise/noise.sh  | 78 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 gallery/noise/config.sh
 create mode 100755 gallery/noise/noise.sh

diff --git a/gallery/noise/config.sh b/gallery/noise/config.sh
new file mode 100644
index 0000000..f930d55
--- /dev/null
+++ b/gallery/noise/config.sh
@@ -0,0 +1,10 @@
+# Config for the 'noise' screensaver
+
+# Name of the screensaver (12 chars max)
+name="noise"
+# Tagline for the screensaver (40 chars max)
+tagline="Retro CRT static noise screensaver"
+description="Relive the analog static noise of the yester-years."
+authors=""
+license="MIT"
+settings=""
diff --git a/gallery/noise/noise.sh b/gallery/noise/noise.sh
new file mode 100755
index 0000000..7e12c18
--- /dev/null
+++ b/gallery/noise/noise.sh
@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# Replicate old-school CRT static noise
+
+# Handler for SIGINT (Ctrl‑C)
+_handle_cleanup_and_exit() {
+  # show the cursor again
+  tput cnorm       
+  tput sgr0
+  echo
+  clear
+  exit 0
+}
+
+# Handler for SIGWINCH (window resize)
+_handle_window_resize() {
+  width="$(tput cols)"
+  height="$(tput lines)"
+  clear
+}
+
+# Capture Ctrl‑C
+trap _handle_cleanup_and_exit SIGINT 
+# Capture SIGWINCH
+trap _handle_window_resize SIGWINCH
+
+# Get terminal dimensions
+width="${COLUMNS:-$(tput cols)}"
+height="${LINES:-$(tput lines)}"
+
+# For portability, we use these UTF codes
+block100="\xe2\x96\x88"  # u2588\0xe2 0x96 0x88 Solid Block 100%
+block75="\xe2\x96\x93"   # u2593\0xe2 0x96 0x93 Dark shade 75%
+block50="\xe2\x96\x92"   # u2592\0xe2 0x96 0x92 Half shade 50%
+block25="\xe2\x96\x91"   # u2591\0xe2 0x96 0x91 Light shade 25%
+block00=' '              # Literal space
+
+blocks=( "${block100}" "${block75}" "${block50}" "${block25}" "${block00}" )
+
+# Randomly select one of the color sets
+# This could be moved to an arg in the future
+# or split to a separate screensaver
+# This would allow desired behaviour to be selectable
+while true; do
+  rand="${RANDOM}"
+
+  # Require range [0, 32766] to evenly divide by 2
+  # Reject 32767 to avoid modulo bias
+  if (( rand < 32767 )); then
+    result=$(( rand % 2 ))
+    if (( result == 0 )); then
+      # Black, white, greys from 256 ANSI set
+      color_set=( 0 7 8 15 16 145 188 {231..255} )  
+    else
+      # Black, white, greys from 256 ANSI set, with RGBY thrown in
+      color_set=( 0 7 8 15 16 145 188 {231..255} 196 46 21 226 )
+    fi
+    break
+  fi
+  # If we're at this line, RANDOM hit 32767!
+done
+
+tput setab 0 # black background
+clear
+tput civis # no cursor
+
+while true; do
+  # Get random location and color
+  x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
+  y=$(( ${SRANDOM:-$RANDOM} % height + 1 ))
+  color_element=$(( ${SRANDOM:-$RANDOM} % ${#color_set[@]} ))
+  color_code="${color_set[color_element]}"
+  block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
+  block=${blocks[block_element]}
+
+  # Print the frame
+  printf -- '%b' "\e[${y};${x}H\e[38;5;${color_code}m${block}"
+done
+

From db18e45abf2b871833a154acf5835aee65d46bfb Mon Sep 17 00:00:00 2001
From: Rawiri Blundell <Rawiri.Blundell@radium.co.nz>
Date: Wed, 29 Oct 2025 23:17:22 +1300
Subject: [PATCH 2/5] noise.sh: Add buffer to improve performance. 
 Benchmarking shows +2.6x improvement.   is based on further benchmarking

---
 gallery/noise/noise.sh | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/gallery/noise/noise.sh b/gallery/noise/noise.sh
index 7e12c18..ed3e5e3 100755
--- a/gallery/noise/noise.sh
+++ b/gallery/noise/noise.sh
@@ -63,6 +63,11 @@ tput setab 0 # black background
 clear
 tput civis # no cursor
 
+# Initialise vars for batching
+buffer=""
+count=0
+batch_size=100
+
 while true; do
   # Get random location and color
   x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
@@ -72,7 +77,15 @@ while true; do
   block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
   block=${blocks[block_element]}
 
-  # Print the frame
-  printf -- '%b' "\e[${y};${x}H\e[38;5;${color_code}m${block}"
+  # Build a buffer of changes to emit
+  buffer+="\e[${y};${x}H\e[38;5;${color_code}m${block}"
+  ((count++))
+
+  # Once the buffer size meets the threshold, dump it and start again
+  if (( count >= batch_size )); then
+    printf -- '%b' "${buffer}"
+    buffer=""
+    count=0
+  fi
 done
 

From 61c356a59b284fb7adf5b20a82b5ded49ed1cbce Mon Sep 17 00:00:00 2001
From: Rawiri Blundell <Rawiri.Blundell@radium.co.nz>
Date: Thu, 30 Oct 2025 08:17:47 +1300
Subject: [PATCH 3/5] gallery/noise/config.sh: Attribution as requested :)

---
 gallery/noise/config.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gallery/noise/config.sh b/gallery/noise/config.sh
index f930d55..2120319 100644
--- a/gallery/noise/config.sh
+++ b/gallery/noise/config.sh
@@ -5,6 +5,6 @@ name="noise"
 # Tagline for the screensaver (40 chars max)
 tagline="Retro CRT static noise screensaver"
 description="Relive the analog static noise of the yester-years."
-authors=""
+authors="Rawiri Blundell"
 license="MIT"
 settings=""

From 7ee35fe7242812587f0060978df95c38c8a80490 Mon Sep 17 00:00:00 2001
From: Rawiri Blundell <Rawiri.Blundell@radium.co.nz>
Date: Thu, 30 Oct 2025 08:20:25 +1300
Subject: [PATCH 4/5] gallery/noise/noise.sh: Add colorless output method

---
 gallery/noise/noise.sh | 94 +++++++++++++++++++++++++++++-------------
 1 file changed, 66 insertions(+), 28 deletions(-)

diff --git a/gallery/noise/noise.sh b/gallery/noise/noise.sh
index ed3e5e3..c6b8217 100755
--- a/gallery/noise/noise.sh
+++ b/gallery/noise/noise.sh
@@ -42,21 +42,23 @@ blocks=( "${block100}" "${block75}" "${block50}" "${block25}" "${block00}" )
 # This would allow desired behaviour to be selectable
 while true; do
   rand="${RANDOM}"
-
-  # Require range [0, 32766] to evenly divide by 2
-  # Reject 32767 to avoid modulo bias
-  if (( rand < 32767 )); then
-    result=$(( rand % 2 ))
+  # Require range [0, 32765] to evenly divide by 3
+  # Reject 32766 and 32767 to avoid modulo bias
+  if (( rand < 32766 )); then
+    result=$(( rand % 3 ))
     if (( result == 0 )); then
       # Black, white, greys from 256 ANSI set
-      color_set=( 0 7 8 15 16 145 188 {231..255} )  
-    else
+      color_set=( 0 7 8 15 16 145 188 {231..255} )
+    elif (( result == 1 )); then
       # Black, white, greys from 256 ANSI set, with RGBY thrown in
       color_set=( 0 7 8 15 16 145 188 {231..255} 196 46 21 226 )
+    else
+      # White only - uses faster emit_without_color()
+      color_set=( 15 )
     fi
     break
   fi
-  # If we're at this line, RANDOM hit 32767!
+  # If we're at this line, RANDOM hit 32766 or 32767!
 done
 
 tput setab 0 # black background
@@ -64,28 +66,64 @@ clear
 tput civis # no cursor
 
 # Initialise vars for batching
+# This eliminates "one pixel change per loop iteration"
+# Benchmarking led to a batch_size selection of 100
 buffer=""
 count=0
 batch_size=100
 
-while true; do
-  # Get random location and color
-  x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
-  y=$(( ${SRANDOM:-$RANDOM} % height + 1 ))
-  color_element=$(( ${SRANDOM:-$RANDOM} % ${#color_set[@]} ))
-  color_code="${color_set[color_element]}"
-  block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
-  block=${blocks[block_element]}
-
-  # Build a buffer of changes to emit
-  buffer+="\e[${y};${x}H\e[38;5;${color_code}m${block}"
-  ((count++))
-
-  # Once the buffer size meets the threshold, dump it and start again
-  if (( count >= batch_size )); then
-    printf -- '%b' "${buffer}"
-    buffer=""
-    count=0
-  fi
-done
+emit_with_color() {
+  while true; do
+    # Get random location and color
+    x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
+    y=$(( ${SRANDOM:-$RANDOM} % height + 1 ))
+    color_element=$(( ${SRANDOM:-$RANDOM} % ${#color_set[@]} ))
+    color_code="${color_set[color_element]}"
+    block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
+    block=${blocks[block_element]}
+
+    # Build a buffer of changes to emit
+    buffer+="\e[${y};${x}H\e[38;5;${color_code}m${block}"
+    ((count++))
+
+    # Once the buffer size meets the threshold, dump it and start again
+    if (( count >= batch_size )); then
+      printf -- '%b' "${buffer}"
+      buffer=""
+      count=0
+    fi
+  done
+}
+
+# In benchmarking, this performs 25-30% faster than emit_with_color()
+# Eliminating the rand calls for color selection clearly has an impact
+# Implicit trust of the terminal color state may have unpredictable results
+# At the end of the day, we're constrained by a shell loop
+# More performance could potentially be gleaned with parallelism (see: forkrun)
+emit_without_color() {
+  color_code="${color_set[*]}"
+  while true; do
+    # Get random location and color
+    x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
+    y=$(( ${SRANDOM:-$RANDOM} % height + 1 ))
+    block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
+    block=${blocks[block_element]}
+
+    # Build a buffer of changes to emit
+    buffer+="\e[${y};${x}H\e[38;5;${color_code}m${block}"
+    ((count++))
+
+    # Once the buffer size meets the threshold, dump it and start again
+    if (( count >= batch_size )); then
+      printf -- '%b' "${buffer}"
+      buffer=""
+      count=0
+    fi
+  done
+}
 
+# Select our output method based on the size of ${color_set[@]}
+case "${#color_set[@]}" in
+  (1) emit_without_color ;;
+  (*) emit_with_color ;;
+esac

From b80121f3590dad7d2d9ff141050a99a9a1cac826 Mon Sep 17 00:00:00 2001
From: Rawiri Blundell <Rawiri.Blundell@radium.co.nz>
Date: Thu, 30 Oct 2025 10:22:51 +1300
Subject: [PATCH 5/5] gallery/noise/noise.sh: Add third mode for greyscale,
 refactor mode selection, define function local vars

---
 gallery/noise/noise.sh | 93 ++++++++++++++++++++++++++++--------------
 1 file changed, 62 insertions(+), 31 deletions(-)

diff --git a/gallery/noise/noise.sh b/gallery/noise/noise.sh
index c6b8217..2516a35 100755
--- a/gallery/noise/noise.sh
+++ b/gallery/noise/noise.sh
@@ -36,31 +36,6 @@ block00=' '              # Literal space
 
 blocks=( "${block100}" "${block75}" "${block50}" "${block25}" "${block00}" )
 
-# Randomly select one of the color sets
-# This could be moved to an arg in the future
-# or split to a separate screensaver
-# This would allow desired behaviour to be selectable
-while true; do
-  rand="${RANDOM}"
-  # Require range [0, 32765] to evenly divide by 3
-  # Reject 32766 and 32767 to avoid modulo bias
-  if (( rand < 32766 )); then
-    result=$(( rand % 3 ))
-    if (( result == 0 )); then
-      # Black, white, greys from 256 ANSI set
-      color_set=( 0 7 8 15 16 145 188 {231..255} )
-    elif (( result == 1 )); then
-      # Black, white, greys from 256 ANSI set, with RGBY thrown in
-      color_set=( 0 7 8 15 16 145 188 {231..255} 196 46 21 226 )
-    else
-      # White only - uses faster emit_without_color()
-      color_set=( 15 )
-    fi
-    break
-  fi
-  # If we're at this line, RANDOM hit 32766 or 32767!
-done
-
 tput setab 0 # black background
 clear
 tput civis # no cursor
@@ -73,6 +48,9 @@ count=0
 batch_size=100
 
 emit_with_color() {
+  local color_set x y color_element color_code
+  local block_element block buffer count batch_size
+  color_set=( 0 7 8 15 16 145 188 {231..255} 196 46 21 226 )
   while true; do
     # Get random location and color
     x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
@@ -95,13 +73,45 @@ emit_with_color() {
   done
 }
 
+# Uses direct color calculation instead of array lookup
+# Benchmarking shows ~11% improvement over emit_with_color()
+# Generates grey shades from ANSI 231-255 (25 shades)
+emit_with_simple_color() {
+  local x y color_code
+  local block_element block buffer count batch_size
+  while true; do
+    # Get random location
+    x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
+    y=$(( ${SRANDOM:-$RANDOM} % height + 1 ))
+
+    # Direct color calculation - no array needed
+    color_code=$(( 231 + ${SRANDOM:-$RANDOM} % 25 ))
+
+    block_element=$(( ${SRANDOM:-$RANDOM} % ${#blocks[@]} ))
+    block=${blocks[block_element]}
+
+    # Build a buffer of changes to emit
+    buffer+="\e[${y};${x}H\e[38;5;${color_code}m${block}"
+    ((count++))
+
+    # Once the buffer size meets the threshold, dump it and start again
+    if (( count >= batch_size )); then
+      printf -- '%b' "${buffer}"
+      buffer=""
+      count=0
+    fi
+  done
+}
+
 # In benchmarking, this performs 25-30% faster than emit_with_color()
 # Eliminating the rand calls for color selection clearly has an impact
 # Implicit trust of the terminal color state may have unpredictable results
 # At the end of the day, we're constrained by a shell loop
 # More performance could potentially be gleaned with parallelism (see: forkrun)
 emit_without_color() {
-  color_code="${color_set[*]}"
+  local x y color_code
+  local block_element block buffer count batch_size
+  color_code=15
   while true; do
     # Get random location and color
     x=$(( ${SRANDOM:-$RANDOM} % width + 1 ))
@@ -122,8 +132,29 @@ emit_without_color() {
   done
 }
 
-# Select our output method based on the size of ${color_set[@]}
-case "${#color_set[@]}" in
-  (1) emit_without_color ;;
-  (*) emit_with_color ;;
-esac
+# Randomly select one of the color modes
+# This could be moved to an arg in the future or split to separate screensavers
+# This would allow desired behaviour to be selectable
+while true; do
+  rand="${RANDOM}"
+  # Require range [0, 32765] to evenly divide by 3
+  # Reject 32766 and 32767 to avoid modulo bias
+  if (( rand < 32766 )); then
+    color_mode=$(( rand % 3 ))
+    case "${color_mode}" in
+      (0)
+        # Greys only - use simple direct calculation (fastest with color)
+        emit_with_simple_color
+      ;;
+      (1)
+        # Greys + accent colors - needs array lookup for RGBY
+        emit_with_color
+      ;;
+      (2)
+        # White only - uses emit_without_color (fastest overall)
+        emit_without_color
+      ;;
+    esac
+  fi
+  # If we're at this line, RANDOM hit 32766 or 32767!
+done