# Trying to debug Pop/PushMatrix -- Can I see the stack?
**URL:** https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170
**Category:** Processing.py
**Created:** [June 26, 2020, 2:12am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170 "2020-06-26T02:12:03Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@slashwreck](https://discourse.processing.org/u/slashwreck)
#### Post date: [June 26, 2020, 2:12am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/1 "2020-06-26T02:12:03Z")
I had some working code, added some simple translation, and now I’m getting `missing a pushMatrix()` error. I believe all my `push`, `pop`, and `translate` commands are balanced, so I don’t see where the error is.
Is there a way to viewthe size of the matrix stack (eg. `len(matrixStack)` so I can isolate where the problem occurs?
I took my code, removed most of the work, and left the matrix-related commands in – I don’t see where I’m unbalanced, `pop`ing more matrices than I `push`. Or else maybe I am missing some basic concept of how this is supposed to work.
The idea is: Start with A4-size page, translate in by a border margin, then iterate through some smaller cells on the upper part of the document, then translate back to the original border-margin point, and retranslate to a point farther down the page.
```auto
def setup():
noLoop()
#initial alignment for Dish Block
translate(0,0) # (redundant)
pushMatrix() #store the default reference frame
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX)
for col in range(COLS):
for row in range(ROWS):
pushMatrix() #store the default reference frame
translate(CELL_WIDTH*col+0.5*CELL_WIDTH, CELL_HEIGHT*row+(0.5*(CELL_HEIGHT-LOWER_CIRCLE_MARGIN_MM*DPMM)))
circle(0,0,PETRI_DIAMETER)
popMatrix() #lose this shifted reference frame
endRecord()
for col in range(COLS):
for row in range(ROWS):
pushMatrix() #store the default reference frame
translate(CELL_WIDTH*col+0.5*CELL_WIDTH, CELL_HEIGHT*row+(0.5*(CELL_HEIGHT-LOWER_CIRCLE_MARGIN_MM*DPMM)))
print("placed {0} bugs in petri {1}".format(count,(col,row)))
popMatrix() #lose this shifted reference frame
for col in range(COLS):
for row in range(ROWS):
pushMatrix() #store the default reference frame
translate(CELL_WIDTH*col, CELL_HEIGHT*row)
name_field = names.pop(0)
popMatrix() #lose this shifted reference frame
endRecord()
#translate to TEXT BLOCK
popMatrix() should go back to original(0,0)
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX+TEXT_BLOCK_HEIGHT_PX)
rect(0,0,TEXT_BLOCK_WIDTH_PX, TEXT_BLOCK_HEIGHT_PX)
print("Done!")
def draw():
pass
```
---
### Author:  [@tabreturn](https://discourse.processing.org/u/tabreturn)
#### Post date: [June 26, 2020, 2:32am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/2 "2020-06-26T02:32:33Z")
I tested your code. It’s working fine for me (like, no errors). I tried this combination of constants:
```auto
BORDER_MARGIN_PX,BORDER_MARGIN_PX,COLS,ROWS,CELL_WIDTH,CELL_HEIGHT,PETRI_DIAMETER,LOWER_CIRCLE_MARGIN_MM,DPMM,BORDER_MARGIN_PX,BORDER_MARGIN_PX,TEXT_BLOCK_HEIGHT_PX,TEXT_BLOCK_WIDTH_PX,TEXT_BLOCK_HEIGHT_PX = 2,2,2,2,2,2,2,2,2,2,2,2,2,2
count, names = 2, [1,2,3,4]
```
Perhaps the problem is somewhere else in your program?
---
### Author:  [@slashwreck](https://discourse.processing.org/u/slashwreck)
#### Post date: [June 26, 2020, 2:44am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/3 "2020-06-26T02:44:58Z")
That’s bizarre. Could it be there is some interaction with my use of `beginRecord` and `endRecord` ??? Because even if I do multiple `pushMatrix()` operations before, it still complains with the same failure on the final `popMatrix()`
The full code below.
```auto
add_library('svg')
# xml.etree module
from xml.etree import ElementTree
import math
import utils
import life
import random as ran
DPMM = 96/25.4 # dots per mm
PAPER_WIDTH_PX = int(210 * DPMM) #A4
PAPER_HEIGHT_PX = int(297 * DPMM) #A4
BORDER_MARGIN_PX = 15 * DPMM
TEXT_BLOCK_HEIGHT_PX = 30 * DPMM
TEXT_BLOCK_WIDTH_PX = PAPER_WIDTH_PX - 2*BORDER_MARGIN_PX
DISH_BLOCK_HEIGHT_PX = PAPER_HEIGHT_PX - 2*BORDER_MARGIN_PX - TEXT_BLOCK_HEIGHT_PX
DISH_BLOCK_WIDTH_PX = PAPER_WIDTH_PX - 2*BORDER_MARGIN_PX
ROWS=3
COLS=2
CELL_HEIGHT = DISH_BLOCK_HEIGHT_PX / ROWS
CELL_WIDTH = DISH_BLOCK_WIDTH_PX / COLS
PETRI_DIAMETER = 0.85*min(CELL_WIDTH, CELL_HEIGHT)
LOWER_CIRCLE_MARGIN_MM = 10#*DPMM
TEXT_SIZE_PX = 0.8*LOWER_CIRCLE_MARGIN_MM * DPMM
print("CELL_HEIGHT {0} CELL_WIDTH {1}".format(CELL_HEIGHT, CELL_WIDTH))
OUTPUT_FN = '.\\graphics\\combined.svg'
def settings():
size(PAPER_WIDTH_PX, PAPER_HEIGHT_PX)
def setup():
noLoop()
svgs = ['.\\graphics\\99_dishes.svg',]
#initial alignment for Dish Block
translate(0,0)
pushMatrix() #store the default reference frame
#even pushing multiple uncessary times results in same failure.
#translate(0,0)
#pushMatrix()
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX)
beginRecord(SVG, svgs[0])
noFill()
for col in range(COLS):
for row in range(ROWS):
pushMatrix() #store the default reference frame
#translate(CELL_WIDTH*col, CELL_HEIGHT*row)
#circle(0.5*CELL_WIDTH,CELL_HEIGHT-0.5*PETRI_DIAMETER-LOWER_CIRCLE_MARGIN_MM*DPMM,PETRI_DIAMETER)
translate(CELL_WIDTH*col+0.5*CELL_WIDTH, CELL_HEIGHT*row+(0.5*(CELL_HEIGHT-LOWER_CIRCLE_MARGIN_MM*DPMM)))
circle(0,0,PETRI_DIAMETER)
popMatrix() #lose this shifted reference frame
endRecord()
#speciesFactory = life.GermSpeciesFactory(PETRI_DIAMETER)
speciesFactory = life.BezierGermSpeciesFactory(PETRI_DIAMETER)
names = []
for col in range(COLS):
for row in range(ROWS):
#factory = ran.choice([life.BezierGermSpeciesFactory(PETRI_DIAMETER),life.GermSpeciesFactory(PETRI_DIAMETER)])
factory = life.BezierGermSpeciesFactory(PETRI_DIAMETER)
singleSpecies = factory.new_species()
print(singleSpecies)
names.append(singleSpecies.name)
bugs = []
svgs.append(".\\graphics\\{0}_cell.svg".format((col,row)))
beginRecord(SVG, svgs[-1])
pushMatrix() #store the default reference frame
#xtrans, ytrans = (CELL_WIDTH*col+0.5*CELL_WIDTH, CELL_HEIGHT*row+0.5*CELL_HEIGHT)
#print("translating to {0}, {1}".format(xtrans, ytrans))
#translate(xtrans, ytrans)
translate(CELL_WIDTH*col+0.5*CELL_WIDTH, CELL_HEIGHT*row+(0.5*(CELL_HEIGHT-LOWER_CIRCLE_MARGIN_MM*DPMM)))
count = 0
for _ in range(ran.randint(0,20)):
#print("col {0} row {1} bug {2}".format(col, row, _))
bugs.append(singleSpecies.germ())
bugs[-1].plot(show_control=False)
count+=1
print("placed {0} bugs in petri {1}".format(count,(col,row)))
#choose specie and quantity
# get list of n-germs, name from a new species
popMatrix() #lose this shifted reference frame
endRecord()
FONT_SIZE=10
svgs.append(".\\graphics\\88_text.svg")
beginRecord(SVG, svgs[-1])
for col in range(COLS):
for row in range(ROWS):
pushMatrix() #store the default reference frame
translate(CELL_WIDTH*col, CELL_HEIGHT*row)
fill(0)
name_field = names.pop(0)
text(name_field,
0.5*CELL_WIDTH,
CELL_HEIGHT-(0.5*LOWER_CIRCLE_MARGIN_MM*DPMM)-0.5*FONT_SIZE,
CELL_WIDTH,
LOWER_CIRCLE_MARGIN_MM*DPMM
)
popMatrix() #lose this shifted reference frame
endRecord()
svgs.append(".\\graphics\\77_title.svg")
beginRecord(SVG, svgs[-1])
#translate to TEXT BLOCK
print("dies here...")
popMatrix() #goes back to original(0,0) ###FAILS HERE
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX+TEXT_BLOCK_HEIGHT_PX)
rect(0,0,TEXT_BLOCK_WIDTH_PX, TEXT_BLOCK_HEIGHT_PX)
endRecord()
# create an empty combined.svg file
beginRecord(SVG, OUTPUT_FN); endRecord()
ElementTree.register_namespace('', 'http://www.w3.org/2000/svg')
tree = ElementTree.parse(OUTPUT_FN)
combined = tree.getroot()
# add the (circles/squares) svgs to the combined.svg file
for svg in svgs:
file = ElementTree.parse(svg).getroot()
group = ElementTree.SubElement(combined, 'g')
group.set('id', svg)
group.set('inkscape:groupmode', 'layer')
group.set('inkscape:label', svg)
for child in file.getchildren():
group.append(child)
# save the changes to the combined.svg file
tree.write(OUTPUT_FN)
if True:
with open(OUTPUT_FN) as f:
s = f.read()
with open(OUTPUT_FN, "w") as f:
old_string = "text style=\"stroke:none;\""
new_string = "text style='stroke:none;text-anchor:middle;dominant-baseline:center'"
s = s.replace(old_string, new_string)
f.write(s)
print("Done!")
def draw():
pass
```
---
### Author:  [@tabreturn](https://discourse.processing.org/u/tabreturn)
#### Post date: [June 26, 2020, 4:49am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/4 "2020-06-26T04:49:29Z")
And if you place an `endRecord()` above the problematic line?
```auto
...
endRecord()
popMatrix() #goes back to original(0,0) ###FAILS HERE
...
```
---
### Author:  [@slashwreck](https://discourse.processing.org/u/slashwreck)
#### Post date: [June 26, 2020, 6:02am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/5 "2020-06-26T06:02:16Z")
Yeah, so I moved the `popMatrix()` outside the begin/endRecord block and it works:
```auto
popMatrix()
svgs.append(".\\graphics\\77_title.svg")
beginRecord(SVG, svgs[-1])
#translate to TEXT BLOCK
print("dies here...")
noFill()
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX+DISH_BLOCK_HEIGHT_PX)
rect(0,0,TEXT_BLOCK_WIDTH_PX, TEXT_BLOCK_HEIGHT_PX)
endRecord()
```
I don’t understand why this is required, as in other blocks, the `popMatrix()` occurs inside a `begin/EndRecord()` Wish there was a way to view ‘the stack’ and figure out what’s going on behind the scenes.
---
### Author:  [@slashwreck](https://discourse.processing.org/u/slashwreck)
#### Post date: [June 26, 2020, 7:18am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/7 "2020-06-26T07:18:46Z")
Feels like there is some weird interaction I don’t understand between `beginRecord` `endRecord` and `*matrix` functions. When I run `printMatrix` inside a record block, for example, it prints two matrices to the console.
for example:
```auto
print("before anything")
printMatrix()
pushMatrix() #store the default reference frame
beginRecord(SVG,svgs[0])
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX)
print("translated BORDER_MARGIN_PX: {0}".format(BORDER_MARGIN_PX))
printMatrix()
noFill()
rect(0,0,10,10)
endRecord()
print("done")
```
yields:
> before anything
> 1.0000 0.0000 0.0000
> 0.0000 1.0000 0.0000
>
> translated BORDER\_MARGIN\_PX: 56.6929133858
> 01.0000 00.0000 56.6929
> 00.0000 01.0000 56.6929
>
> 01.0000 00.0000 56.6929
> 00.0000 01.0000 56.6929
>
> done
---
### Author:  [@slashwreck](https://discourse.processing.org/u/slashwreck)
#### Post date: [June 26, 2020, 7:28am UTC](https://discourse.processing.org/t/trying-to-debug-pop-pushmatrix-can-i-see-the-stack/22170/8 "2020-06-26T07:28:49Z")
Yeah, I’m suspecting that that it maintains a separate transformationMatrix for the SVG recrod I’m creating. When I’m not inside an SVG record, it strictly shows a single matrix:
```auto
print("before anything")
printMatrix()
pushMatrix() #store the default reference frame
beginRecord(SVG,svgs[0])
translate(BORDER_MARGIN_PX, BORDER_MARGIN_PX)
print("translated BORDER_MARGIN_PX: {0}".format(BORDER_MARGIN_PX))
printMatrix()
noFill()
rect(0,0,10,10)
endRecord()
print("done")
print("is this a single?") #yes it's a single
printMatrix()
print("-----")
```
```
>
```
> ```
> before anything
>
> ```
>
> 1.0000 0.0000 0.0000
> 0.0000 1.0000 0.0000
>
> translated BORDER\_MARGIN\_PX: 56.6929133858
> 01.0000 00.0000 56.6929
> 00.0000 01.0000 56.6929
>
> 01.0000 00.0000 56.6929
> 00.0000 01.0000 56.6929
>
> done
> is this a single?
> 01.0000 00.0000 56.6929
> 00.0000 01.0000 56.6929
>
> \_ \_