Fix anchored position rounding #83

FoamyGuy · 2020-08-15T00:05:22Z

This resolves #82. The sample script in that issue and several other variations of it that I tested now result in the label remaining in the same position over time.

kmatch98

In testing of your updated code, this resolves the x-position wandering.

However, I observed y-rounding errors. I am attaching proposed code changes (see the comments) to solve the rounding (I was afraid of making pull request for fear of messing something up, but let me know if that is easier for you and I will figure it out.)

Here is the code where I saw y-movement due to rounding:

print("Display is started")

# load all the fonts
print("loading fonts...")


# Setup file locations for BDF font files
font_files = [
    "fonts/Helvetica-Bold-16.bdf",
    #            'fonts/BitstreamVeraSans-Roman-24.bdf',
    #            'fonts/BitstreamVeraSans-Roman-16.bdf',
    #            'fonts/Fayette-HandwrittenScript-64.bdf',
]


font_list = []

for i, font_file in enumerate(font_files):

    if use_builtinfont:
        this_font = (
            terminalio.FONT
        )  # comment this out to switch back to BDF loaded fonts
    else:
        from adafruit_bitmap_font import bitmap_font

        this_font = bitmap_font.load_font(font_file)

    font_list.append(this_font)


preload_the_glyphs = (
    True  # set this to True if you want to preload the font glyphs into memory
)
# preloading the glyphs will help speed up the rendering of text but will use more RAM

if preload_the_glyphs:

    # identify the glyphs to load into memory -> increases rendering speed
    glyphs = b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-,.:?! "

    print("loading glyphs...")
    for font in font_list:
        if font is not terminalio.FONT:
            font.load_glyphs(glyphs)

    print("Glyphs are loaded.")

print("Fonts completed loading.")

# create group

gc.collect()
print("After creating Group,  Memory free: {}".format(gc.mem_free()))


my_string = "Welcome to using displayio on CircuitPython!"

gc.collect()
label_start_memory = gc.mem_free()
start_time = time.monotonic()

bmap_label = label.Label(
    font=font_list[0],
    text=my_string,
    color=0xFFFFFF,
    max_glyphs=len(my_string),
    background_color=0xFF0000,
    padding_bottom=0,
    padding_left=0,
    padding_right=0,
    padding_top=0,
    background_tight=False,
    x=10,
    y=30,
    line_spacing=1.25,
    scale=my_scale,
    anchor_point=(0.5,0.5),
    anchored_position=(320/2, 240/2),
)
end_time = time.monotonic()

gc.collect()
label_end_memory = gc.mem_free()

bmap_group = displayio.Group(max_size=1)  # Create a group for displaying
bmap_group.append(bmap_label)


print("***")
print("{} memory used: {}".format(version, label_start_memory - label_end_memory))
print("{} time to process: {} seconds".format(version, end_time - start_time))
display.auto_refresh = True

display.show(bmap_group)

while True:
    print("anchor_point: {}, anchored_position: {}".format(bmap_label.anchor_point, bmap_label.anchored_position))
    bmap_label.text='This is a test string'
    time.sleep(0.1)
    time.sleep(1)
    print("anchor_point: {}, anchored_position: {}".format(bmap_label.anchor_point, bmap_label.anchored_position))
    bmap_label.text=my_string
    time.sleep(0.1)
    time.sleep(1)
    pass

kmatch98 · 2020-08-15T16:33:00Z

adafruit_display_text/label.py

@@ -399,7 +402,7 @@ def anchored_position(self, new_position):
            return  # Note: anchor_point must be set before setting anchored_position
        new_x = int(
            new_position[0]
-            - self._anchor_point[0] * (self._boundingbox[2] * self._scale)
+            - round(self._anchor_point[0] * (self._boundingbox[2] * self._scale))
        )
        new_y = int(


Here is my proposed update for the anchored_position setter for variable new_y:

new_y = int(round( new_position[1] - (self._anchor_point[1] * self._boundingbox[3] * self._scale) + ((self._boundingbox[3] * self._scale) / 2.0) ))

kmatch98 · 2020-08-15T16:36:57Z

adafruit_display_text/label.py

+            int(
+                self.x
+                + round(self._anchor_point[0] * self._boundingbox[2] * self._scale)
+            ),
            int(


Here are my proposed changes for the anchored_position y-getter

int(round( self.y + (self._anchor_point[1] * self._boundingbox[3] * self._scale) - ((self._boundingbox[3] * self._scale) / 2.0) )),

FoamyGuy · 2020-08-15T17:32:02Z

Thank you @kmatch98! I'm trying out your changes now.

FoamyGuy · 2020-08-15T17:49:28Z

I was able to use your code and reproduce the y shifting. I tested your changes successfully and it does resolve the shifting. Nice catch! Thank you.

Latest commit adds those changes.

kmatch98 · 2020-08-15T18:08:27Z

@jepler do these fixes solve the moving text bug you observed on your Black Lives Matter Say Their Names display?

kmatch98 · 2020-08-16T22:20:37Z

Reminder: this Rounding bug needs to be corrected on bitmap_label.py

jepler · 2020-08-17T14:22:33Z

No, this doesnb't fix the problem for me. Additionally, it changed the vertical positioning of some labels in my code that were NOT using anchored_point / anchored_position.

These labels were shifted up:

# Create a 3 line set of text for BLM
blm_font = [None, None, None]
for line in range(3):
    label = adafruit_display_text.label.Label(
        font, color=0xFFFFFF, x=8, y=line * 84+12, max_glyphs=16,
    )
    blm_font[line] = label
    blm_group.append(label)

These labels "slide slowly left" as their text is changed repeatedly. Reassigning the anchored_position and anchor_point properties keeps them in position, though

# Create a 2 line set of font text for names
names_font = [None, None]
for line in range(2):
    label = adafruit_display_text.label.Label(
        font,
        color=0xFFFFFF,
        max_glyphs=16,
    )
    # Center each line horizontally, position vertically
    label.anchor_point = (0.5, 0)
    label.anchored_position = (200, line*84+42)
    names_font[line] = label

The full program is https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/master/CircuitPython_SharpDisplay_Displayio/code.py and the font is also in the same folder on github.

jepler · 2020-08-17T14:28:23Z

Here's a reproducer that doesn't actually need the display, but it DOES need the font.

import terminalio
import adafruit_display_text.label
import adafruit_bitmap_font.bitmap_font

font = adafruit_bitmap_font.bitmap_font.load_font("/GothamBlack-54.bdf")
font.load_glyphs(b'Abcdefghijklmnop')

label = adafruit_display_text.label.Label(
    font,
    color=0xFFFFFF,
    max_glyphs=16,
)
# Center each line horizontally, position vertically
label.anchor_point = (0.5, 0)
label.anchored_position = (200, 42)

while True:
    for i in range(16):
        label.text = "Abcdefghijklmnop"[:i]
    print(label.x, label.y)

FoamyGuy · 2020-08-17T14:30:55Z

Thanks for the update jepler. The vertical position changing for some of the texts not using anchored_position definitely is odd to me. I believe those should have been unaffected since our changes were only inside of anchored_position getter and setter. We'll step through the logic in a bit more detail. Perhaps it's being utilized somewhere internally that I am overlooking.

Thanks for sharing this code. We will get it tested out and once we have another attempt at a fix we can test against this project.

jepler · 2020-08-17T14:32:02Z

I will be putting in a PR to work around this issue in the Learn repo's script, so take care to grab the script at https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/d130bff4eb53d5b25edb808c204988e88eb47557/CircuitPython_SharpDisplay_Displayio/code.py for your testing

FoamyGuy · 2020-08-17T14:49:52Z

@jepler I ran your reproducer code on my end on a Wio Terminal device and I don't think I am seeing anything out of the ordinary.

When I run that code and let it go for several seconds I am seeing the same x,y values printed over and over:

FoamyGuy · 2020-08-17T14:52:29Z

Also it's worth noting that when using label.anchor_point = (0.5, 0) it would be expected that the x position could change if the text in the label changes, since the anchor_point is at 50% the left and right edges of the bounding box will get bigger or smaller as text gets added or removed from the label.

However that is only if the actual String within the text is different. Resetting to the same text that is already present should not result in any movement ideally.

FoamyGuy · 2020-08-17T14:58:39Z

One more quick update for now: @jepler are you certain you copied in the edited code from this PR to your device? I reverted back to the "real" display_text library and ran your reproducer and I do see the x position that gets printed changing.

But when I run that same code with the modified display_text library from this PR I always see -132 printed for the x position.

I know you are working on a Sharp display of some sort, I don't have access to try with that, but I am curious what microcontroller are you using? If it is something I have access to I'd like to give this reproducer code a try on my end using the same device if possible.

kmatch98 · 2020-08-17T22:04:44Z

I ran @jepler 's code on my ILI9341 display (320x240) using the currently-released code for label.py and recreated the issue that he observed, with the text position moving (anchored_position is changing).

Without changing the code, I changed the label library to @FoamyGuy 's updated code with the latest commit and this solved the issue, and the anchored_position did not change. (Note: My screen is smaller than the one used by jepler, so it got cut off at the top, but otherwise this code worked fine for me with the library in this PR.)

Also, I found a Black Lives Matter font here (Cornerstone): https://fontmeme.com/fonts/cornerstone-free-font/
and created a large 84 pixel size BDF font that could work for this project: https://gist.github.com/kmatch98/2fc8a6b0f12271b78fc2f4dc84e8cac8

jepler · 2020-08-18T02:04:04Z

It's quite likely I made a mistake in my testing. I'll test again. Thanks for your patience.

Maybe I tested with the wrong code altogether -- I'm sure the behavior CHANGED depending which file I copied, so that points to me testing with the released version and with some unrelated version with other bugs....

jepler · 2020-08-18T14:56:28Z

I tested again and here's what I found:

between adafruit-circuitpython-bundle-6.x-mpy-20200811 and the tip of the main (m-----) branch, the vertical position of the BLACK LIVES MATTER text changed. This text is positioned with x and y and does not use anchored position. It appears to move UP about a half a line.
The tip of the main branch has the shifting left problem
This PR's code does not, the problem appears to be fixed.

The first point seems to an incompatible behavior between the last release 2.8.0 on July 24, which may or may not be intentional. By using anchored_position, I can write code that works with both versions.

jepler

When I re-tested, I determined it fixes the reported problem; the other behavior I identified is not introduced by this PR.

FoamyGuy · 2020-08-18T18:54:59Z

Since we've got confirmation that this resolved the issue and an approving review I am going to go ahead and merge this so that hopefully we will minimize the number of folks that run across the bug in their projects.

With regards to the x,y position changes when not using anchor_point and anchored_position: I will plan to look into this, I do not think any recent changes intentionally changed the behavior of x/y positioning when anchored_position is not in use. So if we can identify when/where it happened we may want to revert it in order to get back to the previous (and documented in many places) behavior.

It is perhaps worth noting the default positioning for label does put the y position at the center of the label vertically. So if you set a label like:

label.x = 0
label.y = 0

The expected behavior is that top half of the text will be off the screen. You will only see the bottom half of the text shown in the top left corner of the display. If the y position getting used moved by half the height my guess is it's related to this default positioning somehow.

Updating https://github.com/adafruit/Adafruit_CircuitPython_EPD to 2.7.0 from 2.6.2: > Merge pull request adafruit/Adafruit_CircuitPython_EPD#41 from makermelissa/master > Merge pull request adafruit/Adafruit_CircuitPython_EPD#40 from makermelissa/master Updating https://github.com/adafruit/Adafruit_CircuitPython_Display_Text to 2.8.1 from 2.8.0: > Merge pull request adafruit/Adafruit_CircuitPython_Display_Text#83 from FoamyGuy/fix_anchored_position_rounding > Merge pull request adafruit/Adafruit_CircuitPython_Display_Text#85 from kmatch98/glyph_speedup > Merge pull request adafruit/Adafruit_CircuitPython_Display_Text#79 from kmatch98/bitmap_label > Merge pull request adafruit/Adafruit_CircuitPython_Display_Text#81 from kmatch98/anchor_fix

FoamyGuy added 2 commits August 14, 2020 18:59

fix anchored position rounding issue

42579f8

black format

ff4be27

kmatch98 requested changes Aug 15, 2020

View reviewed changes

fix y position shifting when text changes

b598e15

jepler approved these changes Aug 18, 2020

View reviewed changes

FoamyGuy merged commit 54acb53 into adafruit:master Aug 18, 2020

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Fix anchored position rounding #83

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