Fix rendered characters have been chipped for some TrueType fonts by tk0miya · Pull Request #45 · python-pillow/Pillow · GitHub

ImageFont ignores descender value of TrueType fonts (uses ascender only),
then some fonts which use descender is chipped on rendering.

This fix is already reported to PIL at http://hg.effbot.org/pil-2009-raclette/issue/13/chipped-characters-have-been-rendered

ImageFont ignores descender value of TrueType fonts (uses ascender only), then some fonts which use descender is chipped on rendering.

Is this in any way controversial or risky? If not, I'm going to merge it. 👍

I woudl like to test it with a font that is actually chipped. The name of one would be helpful.

@tk0miya Can you clarify "some TrueType fonts" i.e. which ones? Thanks

IIRC, I had this applied for a short time in my PIL fork but it broke other cases. I had to revert.

I met this problem with IPA font (http://ossipedia.ipa.go.jp/ipafont/index.html#en )

BTW, In the broken case, the questioner uses HelveticaLTStd-Light.otf .
I wanna try to renderer it, but it seems adobe's non-free fonts...

I'm going to close this until we can figure out what is going on

PIL clipping fonts is a common problem, e.g.:

There's a patch at http://pastebin.com/jP2iLkDN :

diff -ur /tmp/orig/_imagingft.c ./_imagingft.c
--- /tmp/orig/_imagingft.c  2009-10-31 22:44:12.000000000 -0200
+++ ./_imagingft.c  2012-12-12 02:30:31.000000000 -0200
@@ -35,6 +35,9 @@
 #include <freetype/freetype.h>
 #endif

+#include FT_GLYPH_H
+
+
 #if PY_VERSION_HEX < 0x01060000
 #define PyObject_New PyObject_NEW
 #define PyObject_Del PyMem_DEL
@@ -160,7 +163,7 @@

     return (PyObject*) self;
 }
-    
+
 static int
 font_getchar(PyObject* string, int index, FT_ULong* char_out)
 {
@@ -188,7 +191,7 @@
 static PyObject*
 font_getsize(FontObject* self, PyObject* args)
 {
-    int i, x;
+    int i, x, y_max, y_min;
     FT_ULong ch;
     FT_Face face;
     int xoffset;
@@ -212,6 +215,7 @@

     face = NULL;
     xoffset = 0;
+    y_max = y_min = 0;

     for (x = i = 0; font_getchar(string, i, &ch); i++) {
         int index, error;
@@ -229,6 +233,16 @@
         if (i == 0)
             xoffset = face->glyph->metrics.horiBearingX;
         x += face->glyph->metrics.horiAdvance;
+
+        FT_BBox bbox;
+        FT_Glyph glyph;
+        FT_Get_Glyph(face->glyph, &glyph);
+        FT_Glyph_Get_CBox(glyph, FT_GLYPH_BBOX_SUBPIXELS, &bbox);
+        if (bbox.yMax > y_max)
+            y_max = bbox.yMax;
+        if (bbox.yMin < y_min)
+            y_min = bbox.yMin;
+
         last_index = index;
     }

@@ -249,7 +263,7 @@

     return Py_BuildValue(
         "(ii)(ii)",
-        PIXEL(x), PIXEL(self->face->size->metrics.height),
+        PIXEL(x), PIXEL(y_max - y_min),
         PIXEL(xoffset), 0
         );
 }
@@ -330,6 +344,19 @@
     if (mask)
         load_flags |= FT_LOAD_TARGET_MONO;

+    int temp;
+    ascender = 0;
+    for (i = 0; font_getchar(string, i, &ch); i++) {
+        index = FT_Get_Char_Index(self->face, ch);
+        error = FT_Load_Glyph(self->face, index, load_flags);
+        if (error)
+            return geterror(error);
+        glyph = self->face->glyph;
+        temp = (glyph->bitmap.rows - glyph->bitmap_top);
+        if (temp > ascender)
+            ascender = temp;
+    }
+
     for (x = i = 0; font_getchar(string, i, &ch); i++) {
         if (i == 0 && self->face->glyph->metrics.horiBearingX < 0)
             x = -PIXEL(self->face->glyph->metrics.horiBearingX);
@@ -348,7 +375,6 @@
             /* use monochrome mask (on palette images, etc) */
             int xx, x0, x1;
             source = (unsigned char*) glyph->bitmap.buffer;
-            ascender = PIXEL(self->face->size->metrics.ascender);
             xx = x + glyph->bitmap_left;
             x0 = 0;
             x1 = glyph->bitmap.width;
@@ -357,7 +383,7 @@
             if (xx + x1 > im->xsize)
                 x1 = im->xsize - xx;
             for (y = 0; y < glyph->bitmap.rows; y++) {
-                int yy = y + ascender - glyph->bitmap_top;
+                int yy = y + im->ysize - (PIXEL(glyph->metrics.horiBearingY) + ascender);
                 if (yy >= 0 && yy < im->ysize) {
                     /* blend this glyph into the buffer */
                     unsigned char *target = im->image8[yy] + xx;
@@ -377,7 +403,6 @@
             /* use antialiased rendering */
             int xx, x0, x1;
             source = (unsigned char*) glyph->bitmap.buffer;
-            ascender = PIXEL(self->face->size->metrics.ascender);
             xx = x + glyph->bitmap_left;
             x0 = 0;
             x1 = glyph->bitmap.width;
@@ -386,7 +411,7 @@
             if (xx + x1 > im->xsize)
                 x1 = im->xsize - xx;
             for (y = 0; y < glyph->bitmap.rows; y++) {
-                int yy = y + ascender - glyph->bitmap_top;
+                int yy = y + im->ysize - (PIXEL(glyph->metrics.horiBearingY) + ascender);
                 if (yy >= 0 && yy < im->ysize) {
                     /* blend this glyph into the buffer */
                     int i;

Is this the patch you had to revert? Or another one

This patch is another one. I have not tried it. I just pasted it here to keep track of things and so it doesn't get lost.

Got it, thanks

With HelveticaLTStd-Light.otf and my changes, I got clipped characters:

I'll try cgohike's fix later (maybe next weekend).

With a patch from http://pastebin.com/jP2iLkDN and HelveticaLTStd-Light.otf, I got correct image!

I think this patch works fine.

Fix rendered characters have been chipped for some TrueType fonts

That's great! Thanks

@aclark4life sorry for confuse you. My pull request is imcomplete.
It generates clipped image with HelveticaLTStd-Light.otf.

Please use patch from http://pastebin.com/jP2iLkDN that is pasted by cgohike.

Can you send the patch as a pull request? Do you want me to revert this last merge?

This fixes the problem in linux, but introduces the bug in OSX.

This is before the fix in OSX:

After:

We definitely need test coverage on this one.

Sooo am I supposed to just patch on top with: http://pastebin.com/jP2iLkDN ? Or revert, then patch…

Hi @aclark4life
I send new pull request #185. this includes reverting merge and patch http://pastebin.com/jP2iLkDN .
but it does not include any testcases... (i don't know how to test)

Thanks!

Converted setup and teardown methods

via scikit-image/scikit-image@e094b38 * pillow 7.1.0 fails on png files, See scikit-image/scikit-image#4548 * pillow 7.1.1 fails due to python-pillow/Pillow#45

Fix rendered characters have been chipped for some TrueType fonts

103cf49

ImageFont ignores descender value of TrueType fonts (uses ascender only), then some fonts which use descender is chipped on rendering.

aclark4life closed this Mar 12, 2013

aclark4life reopened this Mar 16, 2013

aclark4life added a commit that referenced this pull request Apr 9, 2013

Merge pull request #45 from tk0miya/fix-rendered-chars-have-been-chipped

1a293f9

Fix rendered characters have been chipped for some TrueType fonts

aclark4life merged commit 1a293f9 into python-pillow:master Apr 9, 2013

tk0miya mentioned this pull request Apr 11, 2013

Fix rendered characters have been chipped for some TrueType fonts #185

Merged

radarhere pushed a commit that referenced this pull request Mar 5, 2020

Merge pull request #45 from radarhere/to-pytest

94d0c7c

Converted setup and teardown methods

kba added a commit to OCR-D/core that referenced this pull request Jun 26, 2020

Blacklist Pillow 7.1.0 and 7.1.1

b8b701f

via scikit-image/scikit-image@e094b38 * pillow 7.1.0 fails on png files, See scikit-image/scikit-image#4548 * pillow 7.1.1 fails due to python-pillow/Pillow#45

kba mentioned this pull request Jun 26, 2020

Blacklist Pillow 7.1.0 and 7.1.1 OCR-D/core#527

Merged

nulano mentioned this pull request Sep 9, 2020

Refactor font_getsize and font_render #4910

Merged

Fix rendered characters have been chipped for some TrueType fonts by tk0miya · Pull Request #45 · python-pillow/Pillow · GitHub

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Fix rendered characters have been chipped for some TrueType fonts - #45

Fix rendered characters have been chipped for some TrueType fonts#45aclark4life merged 1 commit intopython-pillow:masterpython-pillow/Pillow:masterfrom tk0miya:fix-rendered-chars-have-been-chippedCopy head branch name to clipboard

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tk0miya commented Jan 31, 2013

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Fix rendered characters have been chipped for some TrueType fonts#45
aclark4life merged 1 commit into
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tk0miya:fix-rendered-chars-have-been-chipped