LMS-2472 refactored image generation script

SVN: 22629

test-data/source/python/screening/canvas.py

+from Quartz import *
+from Cocoa import *
+from LaunchServices import * # for kUTTypePNG
+
+class PlateWellCanvas:
+  """
+  A canvas with utility methods for drawing images for plate wells.
+  
+  The utility methods support drawing source images and overlays and
+  allow the resulting images to be written to files.
+  
+  The canvas uses an underlying CoreGraphics bitmap context with with
+  device RGB color space.
+  """
+  
+  def __init__(self, width = 512, height = 512):
+    """Constructor that takes the size of the canvas."""
+    self.width = width
+    self.height = height
+    self.ctx = self._create_rgba_bitmap_context()
+    
+  def draw_inset_rect(self, r, g, b, start, isUnfilled = 0):
+    ctx = self.ctx
+    with CGSavedGState(ctx):
+      CGContextSetRGBStrokeColor(ctx, r, g, b, 1)
+      if isUnfilled:
+        CGContextSetRGBFillColor(ctx, 0, 0, 0, 0) # transparent
+      else:
+        CGContextSetRGBFillColor(ctx, r, g, b, 1)
+      CGContextSetLineWidth(ctx, 40)
+      CGContextAddRect(ctx, CGRectMake(start, start, self.width - 2 * start, self.height - 2 * start))
+      CGContextDrawPath(ctx, kCGPathFillStroke)
+  
+  def draw_text(self, x, y, text):
+    ctx = self.ctx
+    with CGSavedGState(ctx):
+      CGContextSetRGBStrokeColor(ctx, 0, 0, 0, 1) # black
+      CGContextSetRGBFillColor(ctx, 1, 1, 1, 1) # white
+      CGContextSetTextMatrix(ctx, CGAffineTransformIdentity)
+      CGContextSelectFont(ctx, "Helvetica Neue", 70, kCGEncodingMacRoman)
+      CGContextSetTextDrawingMode(ctx, kCGTextFillStroke)
+      CGContextShowTextAtPoint(ctx, x, y, text, len(text))
+    
+  def write_png_file(self, filename):
+    """Write the graphics context to a PNG file"""
+    ctx = self.ctx
+    image = CGBitmapContextCreateImage(ctx)
+    fileUrl = NSURL.fileURLWithPath_(filename)
+    dest = CGImageDestinationCreateWithURL(fileUrl, kUTTypePNG, 1, None)
+    CGImageDestinationAddImage(dest, image, None)
+    CGImageDestinationFinalize(dest)
+  
+  # Private Methods
+  def _create_rgba_bitmap_context(self):
+    """Create a new CG Graphics Context."""
+    color_space = CGColorSpaceCreateDeviceRGB()
+    pixels_wide = self.width
+    pixels_high = self.height
+    bits_per_component = 8
+    number_of_components = 4 # r,g,b,a
+    # Convert bits per component to bytes per pixel, rounding up to the next int if necessary
+    bytes_per_pixel = (bits_per_component * number_of_components + 7)/8
+    bitmap_bytes_per_row   = (pixels_wide * bytes_per_pixel);
+    # Create an RGB bitmap, let CoreGraphics deal with allocating and managing memory
+    ctx = CGBitmapContextCreate(None, pixels_wide, pixels_high, bits_per_component, bitmap_bytes_per_row, color_space, kCGImageAlphaPremultipliedLast)
+    return ctx
\ No newline at end of file

test-data/source/python/screening/generate-test-images.py

 #!/usr/bin/python
 
-from Quartz import *
-from Cocoa import *
-from LaunchServices import * # for kUTTypePNG
+import canvas
 import math
 import os
 import shutil
@@ -11,51 +9,22 @@ size = 512
 well = "A1"
 tileNum = 6
 
-def createContext():
-  cs = CGColorSpaceCreateDeviceRGB ()
-  pixelsWide = size
-  pixelsHigh = size
-  bits_per_component = 8
-  number_of_components = 4 # r,g,b,a
-  # Convert bits per component to bytes per pixel, rounding up to the next int if necessary
-  bytes_per_pixel = (bits_per_component * number_of_components + 7)/8
-  bitmapBytesPerRow   = (pixelsWide * bytes_per_pixel);
-  bitmapByteCount     = (bitmapBytesPerRow * pixelsHigh);  
-  # Create an RGB bitmap, let CoreGraphics deal with allocating and managing memory
-  ctx = CGBitmapContextCreate(None, pixelsWide, pixelsHigh, bits_per_component, bitmapBytesPerRow, cs, kCGImageAlphaPremultipliedLast)
-  return ctx
-  
-def write_to_png_file(ctx, filename):
-  image = CGBitmapContextCreateImage(ctx)
-  fileUrl = NSURL.fileURLWithPath_(filename)
-  dest = CGImageDestinationCreateWithURL(fileUrl, kUTTypePNG, 1, None);
-  CGImageDestinationAddImage(dest, image, None);
-  CGImageDestinationFinalize(dest);
-
-def drawRect(ctx, r, g, b, start, isUnfilled = 0):
-  with CGSavedGState(ctx):
-    CGContextSetRGBStrokeColor(ctx, r, g, b, 1)
-    if isUnfilled:
-      CGContextSetRGBFillColor(ctx, 0, 0, 0, 0) # transparent
-    else:
-      CGContextSetRGBFillColor(ctx, r, g, b, 1)
-    CGContextSetLineWidth(ctx, 40)
-    CGContextAddRect(ctx, CGRectMake(start, start, size - 2 * start, size - 2 * start))
-    CGContextDrawPath(ctx, kCGPathFillStroke)
+def create_canvas():
+  return canvas.PlateWellCanvas(size, size)
+
+def write_to_png_file(canvas, filename):
+  canvas.write_png_file(filename)
+
+def drawRect(canvas, r, g, b, start, isUnfilled = 0):
+  canvas.draw_inset_rect(r, g, b, start, isUnfilled)
   
-def drawText(ctx, x, y, text):
-  with CGSavedGState(ctx):
-    CGContextSetRGBStrokeColor(ctx, 0, 0, 0, 1) # black
-    CGContextSetRGBFillColor(ctx, 1, 1, 1, 1) # white
-    CGContextSetTextMatrix(ctx, CGAffineTransformIdentity)
-    CGContextSelectFont(ctx, "Helvetica Neue", 70, kCGEncodingMacRoman)
-    CGContextSetTextDrawingMode(ctx, kCGTextFillStroke)
-    CGContextShowTextAtPoint(ctx, x, y, text, len(text))
+def drawText(canvas, x, y, text):
+  canvas.draw_text(x, y, text)
 
 def drawMatrix(coordsList, dir, channel, isOverlay):
   nonemptyTiles = set([ calcTile(coords) for coords in coordsList ])
   for tile in range(1, 10):
-    c = createContext()
+    c = create_canvas()
     if tile in nonemptyTiles:
       if not isOverlay:
         drawRect(c, 0, 0, 0, 0)
@@ -96,7 +65,7 @@ def overlayTests(sampleCode):
 
   
 def save(dir, filename, text, r, g, b, merged = 0):
-  c = createContext()
+  c = create_canvas()
   drawRect(c, 0, 0, 0, 0) # fill with black
   
   zero = 0