I cannot find the right function to add color overlay on another image when transparent areas should remain untouched.
For example on source image there is a semi-transparent white circle and around it everything is fully transparent. When I apply the operation with red color, I'd like to get white/red circle with fully transparent area around it.
On HTML5 canvas, it is achieved by:
layerContext.globalCompositeOperation = "source-atop";
layerContext.fillStyle = color;
layerContext.fillRect(0, 0, w, h);
I tried alpha_composite, blend and composite functions, but maybe misused them.
EDIT: here is what I get using:
overlay = Image.new('RGB', im1.size, (255, 0, 0))
im1.paste(overlay, mask=im1)
Canvas:
PIL:
PIL result is a little bit lighter, but color is the same. Any ideas?
Related
I'm creating a heatmap using Pillow in Python. After painting the heatmap, I want to blank out everything outside a certain area. The area in question is described by a handful of polygons, each containing a couple of thousands of points.
I know how to paint everything inside the polygons (see below), but how do I paint everything outside the polygons? The below examples paints the polygons blue, while it keeps the color of the background. I want to paint the bakground blue, while keeping the color of the polygons.
from PIL import Image, ImageDraw
# This image painted red represents the heatmap.
# In reality, it's not a solid color but the result of some calculations.
image = Image.new("P", (500, 500), 1)
image.putpalette([
0, 0, 255,
255, 0, 0
])
draw = ImageDraw.Draw(image)
# Actual polygon is much more complex.
polygons = [[(100, 100), (100, 400), (350, 50)], [(150, 450), (400, 300), (450, 50)]]
# This is the opposite of what I want. It paints everything in the polygons blue.
# I want everything outside of them blue.
for polygon in polygons:
draw.polygon(polygon, fill=0, outline=None, width=0)
# Look at the result.
image.show()
The approach in this quesiton might be useful, but I'm not sure how to adapt it since I am not interested in transparency, and I am working with palette ("P") images.
I think the secret here is to work out how to draw either:
the polygons, or
everything that is not the polygons
in black on a white background. Once you have that as a "mask", you can use it as the parameter to paste() to control where any new colour or image is pasted onto your existing one.
I've got a function that takes an image and adjusts all of the RGB values by a given amount:
def colour(self,img,col):
img = self.my_image.copy()
col = (col[0],col[1],col[2],0)
img.fill(col, None, pygame.BLEND_RGBA_ADD)
return img
I want to apply this to a partially transparent image. But when I apply this to the image, the transparent pixels become coloured. I want these pixels to stay transparent, but any opaque pixels to be coloured as normal. Is there any way I can do this, without having to loop through every pixel and check if each one is transparent before adjusting it? Thanks
fill treats the color to be solid. You have to use blit.
Create a transparent image the size of the source image and fill it with the color. Finally, mix both images:
def colour(self, img, col):
img = self.my_image.copy()
color_img = pygame.Surface(img.get_size(), pygame.SRCALPHA)
color_img.fill((col[0], col[1], col[2], 0))
img.blit(color_img, (0, 0), special_flags = pygame.BLEND_RGBA_ADD)
return img
See also Is it possible to change sprite colours in Pygame?
I need a bright version of some of my images in pygame. However, I don't want to make a bright version of every single one. Can I change this through pygame?
I've found a similar queation here (How can you edit the brightness of images in PyGame?), but I don't know how to multiply the color of an image. Can someone explain how I can do that?
If you want to brighten an image, then I recommend to add a constant color to the surface. This can be achieved by .fill(), wby the use of the special parameter BLEND_RGB_ADD. If the fill color is black (0, 0, 0) then the image won't change at all. If the fill color is white (255, 255, 255), then the entire image will become white. e.g.:
image = pygame.image.load(my_imagename)
brighten = 128
image.fill((brighten, brighten, brighten), special_flags=pygame.BLEND_RGB_ADD)
[...] I want the image to be more transparent.
If you want to increase the transparency of the image, then yo can "blend" the image with a transparent color, by the use of the special flag BLEND_RGBA_MULT . Of course you've to ensure that the image format provides an alpha channel (e.g. .convert_alpha())
image = pygame.image.load(my_imagename).convert_alpha()
transparency = 128
image.fill((255, 255, 255, transparency), special_flags=pygame.BLEND_RGBA_MULT)
I want to rotate a black and white image. I am trying to use the rotate function as follows:
image.rotate(angle, fillcolor=255)
I am required to older versions of Python and Pillow, and they do not support the 'fillcolor' argument. I cannot upgrade to the newer versions due to certain restrictions and cannot use any external libraries.
Is there another way to fill the area outside the rotated image with white color using Pillow?
Rotated image has black color in the area outside the rotated part. I want to fill it with white color.
Original : Original image
Rotated :Rotated image
You can try Interpolating the Original Image, with the cropped one via Image.composite() to get rid of the black bars/borders.
from PIL import Image
img = Image.open(r"Image_Path").convert("RGBA")
angle = 30
img = img.rotate(angle)
new_img = Image.new('RGBA', img.size, 'white')
Alpha_Image = Image.composite(img, new_img, img)
Alpha_Image = Alpha_Image.convert(img.mode)
Alpha_Image.show()
The above code takes in an Image, converts it into mode RGBA (Alpha is required for this process), and then rotates the Image by 30 degrees. After that It creates a empty Image object of mode RGBA of the same dimensions as the original image, with each pixel having a default value of 255 each channel (i.e Pure white for RGB, and Full Opacity in the context of Alpha/Transparency). Then Interpolates the original image with this empty one using the mask of original Image (we are using the transparency mask of the first image). This results in the Desired images, where black bars/edges are replaced by white. In the end we convert the image color space to the original one.
ORIGINAL IMAGE:-
IMAGE AFTER ROTATING 30 DEGREES:-
An awkward option that has always worked for me, seeing as with my tools I always get a light gray "border" around the rotated image that interferes with filling:
add a border on the non-rotated image and use the fill color with that border.
The bordering operation is lossless and filling will be exact (and easy).
rotate the bordered image. The seam will now also be correct (but not exact unless you
rotate by 45° or 90°).
calculate the size of the rotated border using trigonometry. The result will not be exact (i.e. "131.12 pixel"). Usually you can do this in reverse, starting with an exact border on the rotated image and calculating the border you need to add, and adjust the border width so that the nonrotated border is exact. Example: with a rotated border of 170 pixels you get a nonrotated border of 140.3394 pixels. So you use a 510 pixel rotated border, resulting in the need to add a 421.018 pixel nonrotated border. This is close enough to 421 pixels that it is acceptable.
remove the rotated border.
This also helps avoiding some artefacts near the cut parts of the image that fall off the rotated image.
It has the drawback that you end up with a more massive rotation, with higher memory expenditure and computation time, especially if you use larger borders to increase precision.
Edit: As no external libraries are allowed, I would suggest cropping the rectangle you want and pasting it onto the original image, this could be done with magic numbers (of the rectangle's coordinates), this works for me (you might will need to tweek a little)
im = Image.open("mFul4.png")
rotated = im.rotate(105)
box = (55, 65,200,210)
d = rotated.crop(box=box)
im.paste(d, box=box)
im.save("ex.bmp" )
and the output
Edit2: This is the ugliest way, but it works, you might need to tweak the magic numbers a bit to have it more precise, I was working on your given image, so couldn't tell when i'm overdoing it. It produces the same output
from PIL import Image
im = Image.open("mFul4.png")
angle=105
cos = 0.240959049 # -cos(angle)
d = im.rotate(angle)
pix = d.load()
tri_x = 120
for i in range(4): # 4 triangles
for j in range(tri_x, -1, -1):
for k in range(int((tri_x-j)*cos)+1, -1, -1):
x,y =( j, k )if i <1 else (d.size[0]-j-1, d.size[1]-k-1)
if i in [2,3]:
y, x = (d.size[0] - j-2 , k) if i <3 else (j, d.size[1] - k)
pix[x,y] = (255, 255, 255, 255)
d.show()
I have a gallery application where the users upload photos and my code gives it a border, writes some of the photo attributes on the border and stores it.
image2 = Image.open('media/' + str(image.file))
width, height = image2.size;
image2 = ImageOps.expand(image2, border=(int(width/25),int(height/20),int(width/25),int(height/10)), fill='rgb(0,0,0)')
(Note that here my bottom border is longer than the top because I am writing attributes on the bottom border.)
Now I'm building an edit feature for the uploaded images where the user can change the attributes of the uploaded images. But the attributes that are already written on the border have to be overwritten.
So here, my approach is to put a black patch on the bottom border and re-write the new attributes without changes the top and side borders and without changing the aspect ratio. All of this has to be done using PIL.
Question is how do I put a black box on the bottom border?
I tried ImageOps.fit() as mentioned here https://pillow.readthedocs.io/en/3.3.x/reference/ImageOps.html#PIL.ImageOps.fit, but the aspect ratio doesn't seem to be right and I want to overwrite on the black border a black box and not crop the photo.
To me it seems like the easiest solution is just quickly draw the black pixels in the area that you want using a couple loops and Image.putpixel
from PIL import Image
img = Image.open('red.png')
for x in range(img.width):
for y in range(img.height - 40, img.height):
img.putpixel((x, y), (0, 0, 0))
img.save('red2.png')
The simplest way in my opinion is to create a new black image and paste onto your existing image -
from PIL import Image
im = Image.open('test.png')
blackBox = Image.new(im.mode, (im.width, 50), '#000')
im.paste(blackBox, (0, im.height - blackBox.height))
Alternatively, you could use ImageDraw - http://pillow.readthedocs.io/en/5.2.x/reference/ImageDraw.html - which you could use to draw rectangles and other shapes.
from PIL import Image, ImageDraw
im = Image.open('test.png')
d = ImageDraw.Draw(im)
d.rectangle((0, im.height - 50, im.width, im.height), fill='#000')