How to make random text on gifs? - imagemagick

Question

I want to change the text on gif, change "YOU" to other words, but I do not know how to do it .
source gif

Answer 1

Here is some unix bash code using Imagemagick to do what you want. Note that you did not clean out all the old text completely from your head image and so near about frame 35, there is still a "y" showing.
Input:
What I did was measure a rectangular region in the top part of the head to restrict where the text was drawn. I correct that region by the width and height of the text you want to draw. Then I loop over each of the 45 frames and compute 30 random values for each of the pointsize (between 5 and 18), the x-position and the y-position within the bounds of the box. I save a list of accumulated values to use with the -annotate function to draw the text in the frame. Once I have all frames drawn with random values for the text, I create the final animation.
cd
cd desktop/test
text="test"
wd=180
ht=110
xo=100
yo=60
minsize=5
maxsize=18
dims=`convert -pointsize $maxsize label:"$text" -format "%#" info:`
WxH=`echo $dims | cut -d+ -f1`
twidth=`echo $WxH | cut -dx -f1`
theight=`echo $WxH | cut -dx -f2`
ww=$((wd-twidth))
hh=$((ht-theight))
diffsize=$((maxsize-minsize))
numtext=30
for ((j=0; j<45; j++)); do
list=""
jj=`printf "%02d" $j`
echo "$j"
convert head.gif[$j] -background black -flatten tmp$jj.gif
for ((i=0; i<numtext; i++)); do
psize=`convert xc: -format "%[fx:round($minsize+$diffsize*random())]" info:`
xoff=`convert xc: -format "%[fx:round($xo+$ww*random())]" info:`
yoff=`convert xc: -format "%[fx:round($yo+$hh*random())]" info:`
list="$list -pointsize $psize -annotate +${xoff}+${yoff} '$text'"
done
convert tmp$jj.gif -font arial -fill white $list tmp$jj.gif
done
convert -delay 20 tmp*.gif -loop 0 head_test.gif
rm -f tmp*.gif
cd
If you want the text rotated, then modify the -annotate arguments as follows. Here I rotate -10 degrees counter clockwise, but for annotate, I need to use the equivalent positive rotations, so 350 degrees.
cd
cd desktop/test
text="test"
wd=180
ht=110
xo=100
yo=60
minsize=5
maxsize=18
dims=`convert -pointsize $maxsize label:$text -format "%#" info:`
WxH=`echo $dims | cut -d+ -f1`
twidth=`echo $WxH | cut -dx -f1`
theight=`echo $WxH | cut -dx -f2`
ww=$((wd-twidth))
hh=$((ht-theight))
diffsize=$((maxsize-minsize))
numtext=30
for ((j=0; j<45; j++)); do
list=""
jj=`printf "%02d" $j`
echo "$j"
convert head.gif[$j] -background black -flatten tmp$jj.gif
for ((i=0; i<numtext; i++)); do
psize=`convert xc: -format "%[fx:round($minsize+$diffsize*random())]" info:`
xoff=`convert xc: -format "%[fx:round($xo+$ww*random())]" info:`
yoff=`convert xc: -format "%[fx:round($yo+$hh*random())]" info:`
list="$list -pointsize $psize -annotate 350x350+${xoff}+${yoff} '$text'"
done
convert tmp$jj.gif -font arial -fill white $list tmp$jj.gif
done
convert -delay 20 tmp*.gif -loop 0 head_test.gif
rm -f tmp*.gif
cd