Setting alignment of picture in bounding box when using keep_aspect_ratio

[slkoo-cc]

Is it possible to choose where to align pdf.image when using w, h, and keep_aspect_ratio? Currently it seems to be stuck to the top left corner.
Example:

pdf.image(
    "./assets/logo.png",
    x=pdf.w - pdf.r_margin - 100,
    y=10,
    w=100,
    h=50,
    keep_aspect_ratio=True,
)

[Lucas-C]

Hi @slkoo-cc

Thank you for reaching out 🙂

Next time, could you please try to provide a minimal, autonomous code snippet when opening an issue?
cf. https://stackoverflow.com/help/minimal-reproducible-example

You code is currently too short, and does not make it possible to help you and precisely answer your question.

Using the following code snippet, referencing test/image/png_indexed/flower1.png in this repository:

from fpdf import FPDF

pdf = FPDF()
pdf.add_page()
pdf.image(
    "./test/image/png_indexed/flower1.png",
    x=pdf.w - pdf.r_margin - 100,
    y=10,
    w=100,
    h=50,
    keep_aspect_ratio=True,
)
pdf.output("issue_1702.pdf")

Then this image is positioned at the top RIGHT corner of the PDF document generated: issue_1702.pdf

Does this help you?

Else, could you please provide an autonomous, minimal code snippet that clearly highlights your problem?

[slkoo-cc]

Hi, sorry for didn't provide the minimal code. The problem is when the image is kept in aspect ratio, it is centered inside the bounding box (w=100, h=50). I want the image to be fully aligned to the right margin instead of in the center.

Another code:

from fpdf import FPDF

pdf = FPDF()
pdf.add_page()
pdf.image(
    "./flower1.png",
    x=pdf.w - pdf.r_margin - 50,
    y=10,
    w=50,
    h=100,
    keep_aspect_ratio=True,
)
pdf.output("issue_1702.pdf")

result in slightly shifted down.

The core problem is trying to put the image at top right within a fixed bounding box without margin, but there is no way to put where to anchor the scaled image at.

[Lucas-C]

Hi @slkoo-cc

Interesting.

Thank you for the detailed examples 👍

There is currently no option to directly achieve what you want using only FPDF.image(),
but you could use this approach:

from fpdf import FPDF
from fpdf.image_parsing import preload_image

pdf = FPDF()
pdf.add_page()

img = "./test/image/png_indexed/flower1.png"
dimensions = dict(
    x=pdf.w - pdf.r_margin - 100,
    y=10,
    w=100,
    h=50,
)

# Render the bounding box:
pdf.set_draw_color(255, 0, 0)
pdf.rect(**dimensions, style="D")

# Render image with keep_aspect_ratio=True - center-aligned :
#pdf.image(img, **dimensions, keep_aspect_ratio=True)

# Render image with the correct aspect ratio & right-aligned:
info = preload_image(pdf.image_cache, img)[2]
x, y, w, h = info.scale_inside_box(**dimensions)
x = dimensions["x"] + dimensions["w"] - w # right-align image
pdf.image(img, x, y, w, h)

pdf.output("issue_1702.pdf")

You could put this code in image_right_aligned() function (or a method of a subclass of FPDF) if you want to re-use this approach several times.
If we have other requests for this feature, we could even consider adding a new parameter to FPDF.image() in fpdf2, something like box_align, but I'm not sure this will be useful to many end-users, and the approach I detailed above is not too difficult to use, so maybe it's best not to add one more extra optional parameter to FPDF.image() for now.

Does this solve your issue?

[slkoo-cc]

Thank you, the function sample is helpful. I do need to note that I will have to change both x and y such that it will move to the top right anchor (2nd example with vertical box) to allow any aspect ratio image in the bounding box. Might be nice to have this in the documentation.

[Lucas-C]

I do need to note that I will have to change both x and y such that it will move to the top right anchor (2nd example with vertical box) to allow any aspect ratio image in the bounding box.

Alright.
Then your code should like somehow like this:

info = preload_image(pdf.image_cache, img)[2]
x, y, w, h = info.scale_inside_box(**dimensions)
x = pdf.epw - w # align image to the right
y = pdf.eph - h # align image to the top
pdf.image(img, x, y, w, h)

Might be nice to have this in the documentation.

Agreed, good idea!
We could add a mention of this in the Fitting an image inside a rectangle subsection there:
https://py-pdf.github.io/fpdf2/Images.html#fitting-an-image-inside-a-rectangle

Would you like to submit a Pull Request to document this, @slkoo-cc? 🙂