I am working on an image-generation program, and I have an issue trying to directly edit the pixels of an image.
My original method, which works, was simply:
image = Image.new('RGBA', (width, height), background)
drawing_image = ImageDraw.Draw(image)
# in some loop that determines what to draw and at what color
drawing_image.point((x, y), color)
This works fine, but I thought directly editing pixels might be slightly faster. I plan on using "very" high resolutions (maybe 10000px by 10000px), so even a slight decrease in time per pixel will be a large decrease overall.
I tried using this:
image = Image.new('RGBA', (width, height), background)
pixels = image.load()
# in some loop that determines what to draw and at what color
pixels[x][y] = color # note: color is a hex-formatted string, i.e "#00FF00"
This gives me an error:
Traceback (most recent call last):
File "my_path\my_file.py", line 100, in <module>
main()
File "my_path\my_file.py", line 83, in main
pixels[x][y] = color
TypeError: argument must be sequence of length 2
How does the actual pixels[x][y] work? I seem to be missing a fundamental concept here (I've never worked with directly editing pixels prior to this), or at least just not understanding what arguments are required. I even tried pixels[x][y] = (0, 0, 0), but that raised the same error.
In addition, is there a faster way to edit the pixels? I've heard that using the pixels[x][y] = some_color is faster than drawing to the image, but I'm open to any other faster method.
Thanks in advance!
You need to pass a tuple index as pixels[(x, y)] or simply pixels[x, y], for example:
#-*- coding: utf-8 -*-
#!python
from PIL import Image
width = 4
height = 4
background = (0, 0, 0, 255)
image = Image.new("RGBA", (width, height), background)
pixels = image.load()
pixels[0, 0] = (255, 0, 0, 255)
pixels[0, 3] = (0, 255, 0, 255)
pixels[3, 3] = (0, 0, 255, 255)
pixels[3, 0] = (255, 255, 255, 255)
image.save("image.png")
Related
From the PIL Documentation:
PIL.ImageDraw.Draw.line(xy, fill=None, width=0)
Draws a line between the coordinates in the xy list.
Parameters:
xy – Sequence of either 2-tuples like [(x, y), (x, y), ...] or numeric values like [x, y, x, y, ...].
fill – Color to use for the line.
width – The line width, in pixels. Note that line joins are not handled well, so wide polylines will not look good.
I'm looking for a fix for this issue. A good solution for me would be to have the line drawn by PIL.ImageDraw have rounded ends (capstyle in TKinter). Is there an equivalent in PIL.ImageDraw?
This is what I would like to obtain:
Minimal Working Example:
from PIL import Image, ImageDraw
WHITE = (255, 255, 255)
BLUE = "#0000ff"
MyImage = Image.new('RGB', (600, 400), WHITE)
MyDraw = ImageDraw.Draw(MyImage)
MyDraw.line([100,100,150,200], width=40, fill=BLUE)
MyDraw.line([150,200,300,100], width=40, fill=BLUE)
MyDraw.line([300,100,500,300], width=40, fill=BLUE)
MyImage.show()
Result from MWE:
There are standard option joint='curve' of the ImageDraw.line designed to fix it.
Your example may look like
from PIL import Image, ImageDraw
WHITE = (255, 255, 255)
BLUE = "#0000ff"
MyImage = Image.new('RGB', (600, 400), WHITE)
MyDraw = ImageDraw.Draw(MyImage)
line_points = [(100, 100), (150, 200), (300, 100), (500, 300)]
MyDraw.line(line_points, width=40, fill=BLUE, joint='curve')
MyImage.show()
Special care is required to address the end-points, but joints are fixed.
The result:
I have the same problem as you. However, you can easily solve the problem by simply plotting a circle of the same diameter as the line widths at each vertex. Below is your code, slightly modified, to fix the problem
from PIL import Image, ImageDraw
WHITE = (255, 255, 255)
BLUE = "#0000ff"
RED = "#ff0000"
MyImage = Image.new('RGB', (600, 400), WHITE)
MyDraw = ImageDraw.Draw(MyImage)
# Note: Odd line widths work better for this algorithm,
# even though the effect might not be noticeable at larger line widths
LineWidth = 41
MyDraw.line([100,100,150,200], width=LineWidth, fill=BLUE)
MyDraw.line([150,200,300,100], width=LineWidth, fill=BLUE)
MyDraw.line([300,100,500,300], width=LineWidth, fill=BLUE)
Offset = (LineWidth-1)/2
# I have plotted the connecting circles in red, to show them better
# Even though they look smaller than they should be, they are not.
# Look at the diameter of the circle and the diameter of the lines -
# they are the same!
MyDraw.ellipse ((150-Offset,200-Offset,150+Offset,200+Offset), fill=RED)
MyDraw.ellipse ((300-Offset,100-Offset,300+Offset,100+Offset), fill=RED)
MyImage.show()
I'm somewhat new to pygame and trying to figure out how to make a circle semi-transparent. The trick however is that the background for the circle also has to be transparent. Here is the code I'm talking about:
size = 10
surface = pygame.Surface(size, size), pygame.SRCALPHA, 32)
pygame.draw.circle(
surface,
pygame.Color("black"),
(int(size/2), int(size/2)),
int(size/2), 2)
I tried using surface.set_alpha(127) but that didn't work. I'm assuming because the surface is already transparent.
Any help is appreciated.
A couple things. First, your surface definition should crash, as it missing a parenthesis. It should be:
surface = pygame.Surface((size, size), pygame.SRCALPHA, 32)
I assume that somewhere later in your code, you have something to the effect of:
mainWindow.blit(surface, (x, y))
pygame.display.update() #or flip
Here is your real problem:
>>> import pygame
>>> print pygame.Color("black")
(0, 0, 0, 255)
Notice that 255 at the end. That means that pygame.Color("black") returns a fully opaque color. Whereas (0, 0, 0, 0) would be fully transparent. If you want to set the transparency, define the color directly. That would make your draw function look like:
pygame.draw.circle(
surface,
(0, 0, 0, transparency),
(int(size/2), int(size/2)),
int(size/2), 2)
I want every pixel that is not black to be set to white (or any arbitrary color).
I need this in Python (preferably using PIL, but other libraries can also be considered)
Thanks
Try this:
import sys
from PIL import Image
imin = Image.open(sys.argv[1])
imout = Image.new("RGB", imin.size)
imout.putdata(map(
lambda pixel: (0,0,0) if pixel == (0,0,0) else (255,255,255),
imin.getdata()
)
)
imout.save(sys.argv[2])
Try using Image.blend(). Suppose your image is im.
# conversion matrix: any color to white, black to black
mtx = (1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0)
mask = im.convert("L", mtx) # show() it to get the idea
decal = Image.new("RGB", im.size, (0, 0, 255)) # we fill with blue
Image.blend(im, decal, mask).show() # all black turned blue
This must be way faster than per-pixel lambda calls, especially on large images.
using PIL
c = color_of_choice
out = im.point(lambda i: c if i>0 else i)
I have already taken a look at this question: SO question and seem to have implemented a very similar technique for replacing a single color including the alpha values:
c = Image.open(f)
c = c.convert("RGBA")
w, h = c.size
cnt = 0
for px in c.getdata():
c.putpixel((int(cnt % w), int(cnt / w)), (255, 0, 0, px[3]))
cnt += 1
However, this is very slow. I found this recipe out on the interwebs, but have not had success using it thus far.
What I am trying to do is take various PNG images that consist of a single color, white. Each pixel is 100% white with various alpha values, including alpha = 0. What I want to do is basically colorize the image with a new set color, for instance #ff0000<00-ff>. SO my starting and resulting images would look like this where the left side is my starting image and the right is my ending image (NOTE: background has been changed to a light gray so you can see it since it is actually transparent and you wouldn't be able to see the dots on the left.)
Any better way to do this?
If you have numpy, it provides a much, much faster way to operate on PIL images.
E.g.:
import Image
import numpy as np
im = Image.open('test.png')
im = im.convert('RGBA')
data = np.array(im) # "data" is a height x width x 4 numpy array
red, green, blue, alpha = data.T # Temporarily unpack the bands for readability
# Replace white with red... (leaves alpha values alone...)
white_areas = (red == 255) & (blue == 255) & (green == 255)
data[..., :-1][white_areas.T] = (255, 0, 0) # Transpose back needed
im2 = Image.fromarray(data)
im2.show()
Edit: It's a slow Monday, so I figured I'd add a couple of examples:
Just to show that it's leaving the alpha values alone, here's the results for a version of your example image with a radial gradient applied to the alpha channel:
Original:
Result:
Try this , in this sample we set the color to black if color is not white .
#!/usr/bin/python
from PIL import Image
import sys
img = Image.open(sys.argv[1])
img = img.convert("RGBA")
pixdata = img.load()
# Clean the background noise, if color != white, then set to black.
for y in xrange(img.size[1]):
for x in xrange(img.size[0]):
if pixdata[x, y] == (255, 255, 255, 255):
pixdata[x, y] = (0, 0, 0, 255)
you can use color picker in gimp to absorb the color and see that's rgba color
The Pythonware PIL online book chapter for the Image module stipulates that putpixel() is slow and suggests that it can be sped up by inlining. Or depending on PIL version, using load() instead.
Using Python I want to be able to draw text at different angles using PIL.
For example, imagine you were drawing the number around the face of a clock. The number 3 would appear as expected whereas 12 would we drawn rotated counter-clockwise 90 degrees.
Therefore, I need to be able to draw many different strings at many different angles.
Draw text into a temporary blank image, rotate that, then paste that onto the original image. You could wrap up the steps in a function. Good luck figuring out the exact coordinates to use - my cold-fogged brain isn't up to it right now.
This demo writes yellow text on a slant over an image:
# Demo to add rotated text to an image using PIL
import Image
import ImageFont, ImageDraw, ImageOps
im=Image.open("stormy100.jpg")
f = ImageFont.load_default()
txt=Image.new('L', (500,50))
d = ImageDraw.Draw(txt)
d.text( (0, 0), "Someplace Near Boulder", font=f, fill=255)
w=txt.rotate(17.5, expand=1)
im.paste( ImageOps.colorize(w, (0,0,0), (255,255,84)), (242,60), w)
It's also usefull to know our text's size in pixels before we create an Image object. I used such code when drawing graphs. Then I got no problems e.g. with alignment of data labels (the image is exactly as big as the text).
(...)
img_main = Image.new("RGB", (200, 200))
font = ImageFont.load_default()
# Text to be rotated...
rotate_text = u'This text should be rotated.'
# Image for text to be rotated
img_txt = Image.new('L', font.getsize(rotate_text))
draw_txt = ImageDraw.Draw(img_txt)
draw_txt.text((0,0), rotate_text, font=font, fill=255)
t = img_value_axis.rotate(90, expand=1)
The rest of joining the two images together is already described on this page.
When you rotate by an "unregular" angle, you have to improve this code a little bit. It actually works for 90, 180, 270...
Here is a working version, inspired by the answer, but it works without opening or saving images.
The two images have colored background and alpha channel different from zero to show what's going on. Changing the two alpha channels from 92 to 0 will make them completely transparent.
from PIL import Image, ImageFont, ImageDraw
text = 'TEST'
font = ImageFont.truetype(r'C:\Windows\Fonts\Arial.ttf', 50)
width, height = font.getsize(text)
image1 = Image.new('RGBA', (200, 150), (0, 128, 0, 92))
draw1 = ImageDraw.Draw(image1)
draw1.text((0, 0), text=text, font=font, fill=(255, 128, 0))
image2 = Image.new('RGBA', (width, height), (0, 0, 128, 92))
draw2 = ImageDraw.Draw(image2)
draw2.text((0, 0), text=text, font=font, fill=(0, 255, 128))
image2 = image2.rotate(30, expand=1)
px, py = 10, 10
sx, sy = image2.size
image1.paste(image2, (px, py, px + sx, py + sy), image2)
image1.show()
The previous answers draw into a new image, rotate it, and draw it back into the source image. This leaves text artifacts. We don't want that.
Here is a version that instead crops the area of the source image that will be drawn onto, rotates it, draws into that, and rotates it back. This means that we draw onto the final surface immediately, without having to resort to masks.
def draw_text_90_into (text: str, into, at):
# Measure the text area
font = ImageFont.truetype (r'C:\Windows\Fonts\Arial.ttf', 16)
wi, hi = font.getsize (text)
# Copy the relevant area from the source image
img = into.crop ((at[0], at[1], at[0] + hi, at[1] + wi))
# Rotate it backwards
img = img.rotate (270, expand = 1)
# Print into the rotated area
d = ImageDraw.Draw (img)
d.text ((0, 0), text, font = font, fill = (0, 0, 0))
# Rotate it forward again
img = img.rotate (90, expand = 1)
# Insert it back into the source image
# Note that we don't need a mask
into.paste (img, at)
Supporting other angles, colors etc is trivial to add.
Here's a fuller example of watermarking diagonally. Handles arbitrary image ratios, sizes and text lengths by calculating the angle of the diagonal and font size.
from PIL import Image, ImageFont, ImageDraw
import math
# sample dimensions
pdf_width = 1000
pdf_height = 1500
#text_to_be_rotated = 'Harry Moreno'
text_to_be_rotated = 'Harry Moreno (morenoh149#gmail.com)'
message_length = len(text_to_be_rotated)
# load font (tweak ratio based on your particular font)
FONT_RATIO = 1.5
DIAGONAL_PERCENTAGE = .5
diagonal_length = int(math.sqrt((pdf_width**2) + (pdf_height**2)))
diagonal_to_use = diagonal_length * DIAGONAL_PERCENTAGE
font_size = int(diagonal_to_use / (message_length / FONT_RATIO))
font = ImageFont.truetype(r'./venv/lib/python3.7/site-packages/reportlab/fonts/Vera.ttf', font_size)
#font = ImageFont.load_default() # fallback
# target
image = Image.new('RGBA', (pdf_width, pdf_height), (0, 128, 0, 92))
# watermark
opacity = int(256 * .5)
mark_width, mark_height = font.getsize(text_to_be_rotated)
watermark = Image.new('RGBA', (mark_width, mark_height), (0, 0, 0, 0))
draw = ImageDraw.Draw(watermark)
draw.text((0, 0), text=text_to_be_rotated, font=font, fill=(0, 0, 0, opacity))
angle = math.degrees(math.atan(pdf_height/pdf_width))
watermark = watermark.rotate(angle, expand=1)
# merge
wx, wy = watermark.size
px = int((pdf_width - wx)/2)
py = int((pdf_height - wy)/2)
image.paste(watermark, (px, py, px + wx, py + wy), watermark)
image.show()
Here it is in a colab https://colab.research.google.com/drive/1ERl7PiX6xKy5H9EEMulBKPgglF6euCNA?usp=sharing you should provide an example image to the colab.
I'm not saying this is going to be easy, or that this solution will necessarily be perfect for you, but look at the documentation here:
http://effbot.org/imagingbook/pil-index.htm
and especially pay attention to the Image, ImageDraw, and ImageFont modules.
Here's an example to help you out:
import Image
im = Image.new("RGB", (100, 100))
import ImageDraw
draw = ImageDraw.Draw(im)
draw.text((50, 50), "hey")
im.rotate(45).show()
To do what you really want you may need to make a bunch of separate correctly rotated text images and then compose them all together with some more fancy manipulation. And after all that it still may not look great. I'm not sure how antialiasing and such is handled for instance, but it might not be good. Good luck, and if anyone has an easier way, I'd be interested to know as well.
If you a using aggdraw, you can use settransform() to rotate the text. It's a bit undocumented, since effbot.org is offline.
# Matrix operations
def translate(x, y):
return np.array([[1, 0, x], [0, 1, y], [0, 0, 1]])
def rotate(angle):
c, s = np.cos(angle), np.sin(angle)
return np.array([[c, -s, 0], [s, c, 0], [0, 0, 1]])
def draw_text(image, text, font, x, y, angle):
"""Draw text at x,y and rotated angle radians on the given PIL image"""
m = np.matmul(translate(x, y), rotate(angle))
transform = [m[0][0], m[0][1], m[0][2], m[1][0], m[1][1], m[1][2]]
draw = aggdraw.Draw(image)
draw.settransform(transform)
draw.text((tx, ty), text, font)
draw.settransform()
draw.flush()