Is there any way to fit an image in pptx without changing the aspect ratio of an image using python pptx package

Question

I have a task to create water mark in images and create pptx using these images and i should not change the aspect ratio of an image as per the rules

Image ratio = 4000x6016

Without changing the ratio, images are not fitting inside the pptx Is there any way to fit an image in pptx without changing the aspect ratio of an image using python pptx package

Expected ouput:

current ouput

Code:

from wand.image import Image
from pptx import Presentation
from pptx.util import Inches
prs = Presentation()
blankSideLayout = prs.slide_layouts[4]

def makePPTX(path):
   slide = prs.slides.add_slide(blankSideLayout)
   slide.shapes.title.text = "sample title"
   slide.placeholders[2].text = "Sample Sub Title" 
   slide.shapes.add_picture(path, Inches(1), Inches(3))
   prs.save("slides.pptx")

logoImg = Image(filename='logo.jpg')
logoImg.transparentize(0.33)
  
img = Image(filename='img.jpg')

img.composite_channel("all_channels",logoImg,"dissolve",20,20)
    
img.save(filename='imgwatermark.jpg')

makePPTX('imgwatermark.jpg')
    

Answer 1

Yes. In my project (md2pptx) I do this.

Essentially you

1. Work out the dimensions of the graphic and the space you want to fit it in.
2. You figure out which dimension you need to scale by and by how much. Answers to 1. guide you in this.
3. You create the graphic scaling according to 2.

Here's code from the md2pptx repo:

def scalePicture(maxPicWidth, maxPicHeight, imageWidth, imageHeight):
    heightIfWidthUsed = maxPicWidth * imageHeight / imageWidth
    widthIfHeightUsed = maxPicHeight * imageWidth / imageHeight

    if heightIfWidthUsed > maxPicHeight:
        # Use the height to scale
        usingHeightToScale = True

        picWidth = widthIfHeightUsed
        picHeight = maxPicHeight

    else:
        # Use the width to scale
        usingHeightToScale = False

        picWidth = maxPicWidth
        picHeight = heightIfWidthUsed
    return (picWidth, picHeight, usingHeightToScale)

The main difficulty is going to be figuring out the dimensions of the source graphic.

Here is some code I borrowed for that:

import imghdr, struct

def get_image_size(fname):
    """Determine the image type of fhandle and return its size.
    from draco"""
    try:
        with open(fname, "rb") as fhandle:
            head = fhandle.read(24)
            if len(head) != 24:
                return -1, -1
            if imghdr.what(fname) == "png":
                check = struct.unpack(">i", head[4:8])[0]
                if check != 0x0D0A1A0A:
                    return
                width, height = struct.unpack(">ii", head[16:24])
            elif imghdr.what(fname) == "gif":
                width, height = struct.unpack("<HH", head[6:10])
            elif imghdr.what(fname) == "jpeg":
                try:
                    fhandle.seek(0)  # Read 0xff next
                    size = 2
                    ftype = 0
                    while not 0xC0 <= ftype <= 0xCF:
                        fhandle.seek(size, 1)
                        byte = fhandle.read(1)
                        while ord(byte) == 0xFF:
                            byte = fhandle.read(1)
                        ftype = ord(byte)
                        size = struct.unpack(">H", fhandle.read(2))[0] - 2
                    # We are at a SOFn block
                    fhandle.seek(1, 1)  # Skip 'precision' byte.
                    height, width = struct.unpack(">HH", fhandle.read(4))
                except Exception:  # IGNORE:W0703
                    return
            else:
                return
            return width, height
    except EnvironmentError:
        return -1, -1