120 lines
3.8 KiB
Lua
120 lines
3.8 KiB
Lua
--[[
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Simple Graphics: An unopinionated graphics API to make hand-made GUIs easy.
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Author: Andrew Lalis <andrewlalisofficial@gmail.com>
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]]--
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local lib = {}
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-- Clears a screen or terminal. If c is not nil then the background color will
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-- be set prior to clearing.
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function lib.clear(m, c)
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if c ~= nil then m.setBackgroundColor(c) end
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m.clear()
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end
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-- Fills a rectangle from the given X and Y coordinates, with a width and
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-- height given by w and h respectively. If c is not nil, then the background
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-- color is set to c.
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function lib.fillRect(m, x, y, w, h, c)
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if c ~= nil then m.setBackgroundColor(c) end
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for i = 1, w do
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for j = 1, h do
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m.setCursorPos(x+i-1, y+j-1)
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m.write(" ")
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end
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end
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end
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-- Draws the outline of a rectangle from the given x and y coordinates with a
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-- width and height given by w and h respectively. If c is not nil, then the
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-- color of the border is set to c.
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function lib.drawRect(m, x, y, w, h, c)
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if c ~= nil then m.setBackgroundColor(c) end
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lib.drawXLine(x, x+w-1, y, c)
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lib.drawXLine(x, x+w-1, y+h-1, c)
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lib.drawYLine(y+1, y+h-2, x, c)
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lib.drawYLine(y+1, y+h-2, x+w-1, c)
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end
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-- Draws a horizontal line from x1 to x2 on the given y level.
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function lib.drawXLine(m, x1, x2, y, bg, fg, char)
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char = char or " "
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if bg ~= nil then m.setBackgroundColor(bg) end
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if fg ~= nil then m.setTextColor(fg) end
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for x = x1, x2 do
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m.setCursorPos(x, y)
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m.write(char)
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end
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end
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-- Draws a vertical line from y1 to y2, on the given x level.
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function lib.drawYLine(m, y1, y2, x, bg, fg, char)
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char = char or " "
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if bg ~= nil then m.setBackgroundColor(bg) end
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if fg ~= nil then m.setTextColor(fg) end
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for y = y1, y2 do
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m.setCursorPos(x, y)
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m.write(char)
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end
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end
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-- Draws text starting at the given x y position.
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function lib.drawText(m, x, y, text, fg, bg)
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if fg ~= nil then m.setTextColor(fg) end
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if bg ~= nil then m.setBackgroundColor(bg) end
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m.setCursorPos(x, y)
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m.write(text)
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end
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-- Draws text such that the center of the text is aligned with the given
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-- x and y coordinates.
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function lib.drawTextCenter(m, x, y, text, fg, bg)
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lib.drawText(m, x-(#text/2)+1, y, text, fg, bg)
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end
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-- Draws a button as a plain rectangle with the given background color, and
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-- centered text drawn with the foreground color. Returns a table containing
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-- x1, y1, x2, y2 coordinates for handling the button's event later.
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function lib.drawButton(m, x, y, w, h, text, fg, bg)
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local x1 = x
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local y1 = y
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local x2 = x+w-1
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local y2 = y+h-1
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local midX = x+math.floor(w/2)
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local midY = y+math.floor(h/2)
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lib.fillRect(m, x, y, w, h, bg)
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lib.drawTextCenter(m, midX, midY, text, fg)
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return {x1=x1,y1=y1,x2=x2,y2=y2}
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end
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-- Determines if a button is pressed, given the event x and y coordinates and
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-- the button's coordinates.
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function lib.isButtonPressed(x, y, buttonCoords)
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return x >= buttonCoords.x1 and x <= buttonCoords.x2 and
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y >= buttonCoords.y1 and y <= buttonCoords.y2
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end
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-- Creates a new button registry table, which is used for registering button
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-- positions and callbacks for event handling.
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function lib.createButtonRegistry()
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return {}
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end
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-- Adds a new button to a registry, so that `handleButtonPress` can invoke the
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-- callback if the button is pressed.
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function lib.registerButton(registry, buttonPos, callback)
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table.insert(registry, {pos=coords,callback=callback})
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end
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-- Handles a recent interaction on the screen that's interpreted as a button
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-- press, by looking for registered buttons whose areas include the given X Y
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-- coordinates.
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function lib.handleButtonPress(registry, x, y)
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for _, button in pairs(registry) do
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if lib.isButtonPressed(x, y, button.pos) then
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button.callback()
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end
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end
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end
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return lib |