Finding the Bounding Box of Plotted Text

finding the bounding box of plotted text

Maybe the strwidth and strheight functions can help here

stroverlap <- function(x1,y1,s1, x2,y2,s2) {
  sh1 <- strheight(s1)
  sw1 <- strwidth(s1)
  sh2 <- strheight(s2)
  sw2 <- strwidth(s2)

  overlap <- FALSE
  if (x1<x2) 
    overlap <- x1 + sw1 > x2
  else
    overlap <- x2 + sw2 > x1

  if (y1<y2)
    overlap <- overlap && (y1 +sh1>y2)
  else
    overlap <- overlap && (y2+sh2>y1)

  return(overlap)
}
stroverlap(.5,.5,"word", .6,.5, "word")

Calculate bounding box of text on plot including text below baseline

Try

plot( 1:10, 1:10 )
text(3, 7, ex <- expression("sample"), adj=c(0,0), cex=3 ) 
sh <- strheight(ex)
abline( h=c( 7, 7+3*sh  ) )

Finding the space a text takes on a matplotlib plot

You can use get_tightbox() method on the Text object and invert transform this to your Data scale with:

# text is your text object
ax.transData.inverted().transform(text.get_tightbox(fig.canvas.get_renderer())

This will return coordinates for a bounding box in format of [[bottom_left_x, bottom_left_y],[top_right_x, top_right_y]].

You can get the text object via get_children method on your ax object and selecting the right object by index, or by assigning ax.annotate method output to a variable.

In your code, you could do something like:

text = ax.annotate('some text', xy=(x,y))
[x1,y1],[x2,y2]=ax.transData.inverted().transform(text.get_tightbbox(f.canvas.get_renderer()))

If you then use this data to plot a bounding box with:

rect = plt.Rectangle([x1,y1],(x2-x1),(y2-y1), edgecolor = 'red', linewidth = 2 ,facecolor='white')
ax.add_patch(rect)

You will get this output with a bounding box drawn around the text:

Why are the Bounding Boxes from Tesseract not aligned on the image text?

This is simply because the x, y co-ordinates of images are counted from the top left, whereas rect counts from the bottom left. The image is 480 pixels tall, so we can do:

plot(image)
rect(
  xleft = text$x1[1], 
  ybottom = 480 - text$y1[1], 
  xright = text$x2[1], 
  ytop = 480 - text$y2[1])

Or, to show this generalizes:

plot(image)

rect(
  xleft = text$x1, 
  ybottom = magick::image_info(image)$height - text$y1, 
  xright = text$x2, 
  ytop = magick::image_info(image)$height - text$y2,
  border = sample(128, nrow(text)))

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