development of graphics module

lib/impure/graphics.nim

@@ -0,0 +1,203 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2010 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements graphical output for Nimrod; the current
+## implementation uses SDL but the interface is meant to support multiple
+## backends some day. 
+
+import sdl, colors
+
+type
+  TRect* = tuple[x, y, width, height: int]
+  TPoint* = tuple[x, y: int]
+
+  PSurface* = ref TSurface ## a surface to draw onto
+  TSurface {.pure, final.} = object
+    w, h: int
+    s: sdl.PSurface
+  
+proc surfaceFinalizer(s: PSurface) = sdl.freeSurface(s.s)
+  
+proc newSurface*(width, height: int): PSurface =
+  ## creates a new surface.
+  new(result, surfaceFinalizer)
+  result.w = width
+  result.h = height
+  result.s = SDL.CreateRGBSurface(SDL.SWSURFACE, width, height, 
+      32, 0x00FF0000, 0x0000FF00, 0x000000FF, 0xff000000)
+
+proc textBounds*(text: string): tuple[len, height: int]
+proc drawText*(sur: PSurface, p: TPoint, text: string)
+
+proc writeToPNG*(sur: PSurface, filename: string) =
+  ## writes the contents of the surface `sur` to the file `filename`.
+  
+
+type
+  TPixels = array[0..1000_000-1, int32]
+  PPixels = ptr TPixels
+
+template setPix(video, pitch, x, y, col: expr): expr =
+  video[y * pitch + x] = col
+
+template getPix(video, pitch, x, y: expr): expr = 
+  video[y * pitch + x]
+
+const
+  ColSize = 4
+
+proc getPixel(sur: PSurface, x, y: Natural): TColor =
+  result = getPix(PPixels(sur.pixels), sur.pitch div ColSize, x, y)
+
+proc setPixel(sur: PSurface, x, y: Natural; col: TColor) =
+  setPix(PPixels(sur.pixels), sur.pitch div ColSize, x, y, col)
+
+proc `[]`*(sur: PSurface, p: TPoint): TColor =
+  result = getPixel(sur, p.x, p.y)
+
+proc `[,]`*(sur: PSurface, x, y: int): TColor =
+  result = setPixel(sur, x, y)
+
+proc `[]=`*(sur: PSurface, p: TPoint, col: TColor) = 
+  setPixel(sur, p.x, p.y, col)
+
+proc `[,]=`*(sur: PSurface, x, y: int, col: TColor) =
+  setPixel(sur, x, y, col)
+
+proc drawCircle*(sur: PSurface, p: TPoint, r: Natural, color: TColor) =
+  ## draws a circle with center `p` and radius `r` with the given color
+  ## onto the surface `sur`.
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  var p = 1 - r
+  var py = r
+  var px = 0
+  var x = p.x
+  var y = p.y
+  while px <= py + 1:
+    setPix(video, pitch, x + px, y + py, color)
+    setPix(video, pitch, x + px, y - py, color)
+    setPix(video, pitch, x - px, y + py, color)
+    setPix(video, pitch, x - px, y - py, color)
+
+    setPix(video, pitch, x + py, y + px, color)
+    setPix(video, pitch, x + py, y - px, color)
+    setPix(video, pitch, x - py, y + px, color)
+    setPix(video, pitch, x - py, y - px, color)
+
+    if p < 0:
+      p = p + (2 * px + 3)
+    else:
+      p = p + (2 * (px - py) + 5)
+      py = py - 1
+    px = px + 1
+
+proc drawLine*(sur: PSurface, p1, p2: TPoint, color: TColor) =
+  ## draws a line between the two points `p1` and `p2` with the given color
+  ## onto the surface `sur`.
+  var x0: int = p1.x
+  var x1: int = p2.x
+  var y0: int = p1.y
+  var y1: int = p2.y
+  var dy: int = y1 - y0
+  var dx: int = x1 - x0
+  if dy < 0:
+    dy = -dy 
+    stepy = -1
+  else:
+    stepy = 1
+  if dx < 0:
+    dx = -dx
+    stepx = -1
+  else:
+    stepx = 1
+  dy = dy * 2 
+  dx = dx * 2
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  setPix(video, pitch, x0, y0, color)
+  if dx > dy:
+    var fraction = dy - (dx div 2)
+    while x0 != x1:
+      if fraction >= 0:
+        y0 = y0 + stepy
+        fraction = fraction - dx
+      x0 = x0 + stepx
+      fraction = fraction + dy
+      setPix(video, pitch, x0, y0, color)
+  else:
+    var fraction = dx - (dy div 2)
+    while y0 != y1:
+      if fraction >= 0:
+        x0 = x0 + stepx
+        fraction = fraction - dy
+      y0 = y0 + stepy
+      fraction = fraction + dx
+      setPix(video, pitch, x0, y0, color)
+
+proc drawHorLine*(sur: PSurface, x, y, w: Natural, Color: TColor) =
+  ## draws a horizontal line from (x,y) to (x+w-1, h).
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  for i = 0 .. w-1: setPix(video, pitch, x + i, y, color)
+
+proc drawVerLine*(sur: PSurface, x, y, h: Natural, Color: TColor) =
+  ## draws a vertical line from (x,y) to (x, y+h-1).
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  for i in 0 .. h-1: setPix(video, pitch, x, y + i, color)
+
+proc fillCircle*(s: PSurface, p: TPoint, r: Natural, color: TColor) =
+  ## draws a circle with center `p` and radius `r` with the given color
+  ## onto the surface `sur` and fills it.
+  var p = 1 - r
+  var py: int = r
+  var px = 0
+  var x = p.x
+  var y = p.y
+  while px <= py:
+    # Fill up the middle half of the circle
+    DrawVerLine(s, x + px, y, py + 1, color)
+    DrawVerLine(s, x + px, y - py, py, color)
+    if px != 0:
+      DrawVerLine(s, x - px, y, py + 1, color)
+      DrawVerLine(s, x - px, y - py, py, color)
+    if p < 0:
+      p = p + (2 * px + 3)
+    else:
+      p = p + (2 * (px - py) + 5)
+      py = py - 1
+      # Fill up the left/right half of the circle
+      if py >= px:
+        DrawVerLine(s, x + py + 1, y, px + 1, color)
+        DrawVerLine(s, x + py + 1, y - px, px, color)
+        DrawVerLine(s, x - py - 1, y, px + 1, color)
+        DrawVerLine(s, x - py - 1, y - px,  px, color)
+    px = px + 1
+
+proc drawRect*(sur: PSurface, r: TRect, color: TColor) =
+  ## draws a rectangle.
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  for i in 0 .. r.w-1:
+    setPix(video, pitch, r.x + i, r.y, color)
+  for i in 0 .. r.h-1:
+    setPix(video, pitch, r.x, r.y + i, color)
+    setPix(video, pitch, r.x + r.w - 1, r.y + i, color)
+  for i in 0 .. r.w-1:
+    setPix(video, pitch, r.x + i, r.y + r.h - 1, color)
+    
+proc fillRect*(sur: PSurface, r: TRect, col: TColor) =
+  ## draws and fills a rectancle.
+  var video = sur.pixels
+  var pitch = sur.pitch div ColSize
+  for i in r.y..y+r.h-1:
+    for j in r.x..r.x+r.w-1: 
+      setPix(video, pitch, j, i, color)
+