paintutils.drawImage incorrectly modifies terminal background color

[WorldChallenge1]

Minecraft Version

1.20.1

Version

1.133.0 (Fabric)

Details

Description

The paintutils.drawImage() function incorrectly modifies the terminal's background color when drawing an image, even when the image should not affect the background color outside of the drawn area.

Expected Behavior

After calling paintutils.drawImage(), the terminal's background color should remain unchanged from what was set before the function call. The function should only modify pixels within the bounds of the drawn image.

Actual Behavior

The terminal's background color is changed after calling paintutils.drawImage(), affecting the entire terminal's background color setting.

Steps to Reproduce

• Set a specific background color using term.setBackgroundColor()
• Clear the terminal and note the current background color
• Parse an image using paintutils.parseImage()
• Draw the image using paintutils.drawImage()
• Check the background color after drawing - it will have changed

Reproduction Code

-- Bug reproduction for paintutils.drawImage changing background color
term.setBackgroundColor(colors.cyan)
term.clear()
term.setCursorPos(1, 1)

current_color = term.getBackgroundColour()
print("Current color: " .. tostring(current_color))

local sprite = [[
 55
5555
5555
 55 ]]

local image = paintutils.parseImage(sprite)
paintutils.drawImage(image, 10, 5) -- Bug occurs here

color_after = term.getBackgroundColour()
print("Color after drawing image: " .. tostring(color_after))
if current_color == color_after then
    print("Background color unchanged after drawing image.")
else
    print("Background color changed after drawing image!")
end

[WorldChallenge1]

For anyone else facing this bug, as a workaround in the mean time you can store the current color with term.getBackgroundColour() before drawing the image and then setting it after drawing the image with term.setBackgroundColour()

Example:

-- Bug reproduction for paintutils.drawImage changing background color
term.setBackgroundColor(colors.cyan)
term.clear()
term.setCursorPos(1, 1)

current_color = term.getBackgroundColour()
print("Current color: " .. tostring(current_color))

local sprite = [[
 55
5555
5555
 55 ]]

local image = paintutils.parseImage(sprite)
paintutils.drawImage(image, 10, 5) -- Bug occurs here
term.setBackgroundColor(current_color) -- add this line

color_after = term.getBackgroundColour()
print("Color after drawing image: " .. tostring(color_after))
if current_color == color_after then
    print("Background color unchanged after drawing image.")
else
    print("Background color changed after drawing image!")
end