Need Help Fixing A Glyph Position

[solomancode]

Hi @wezm ,

Thank you, I really appreciate how you always get back to me so quickly with answers.

I need some help rendering the Arabic word "ٱللَّهَ" correctly

Issue

The last glyph colored in "Blue" should be positioned similar to its corresponding glyph in the word below.

This is the layout details for the last glyph

"glyph_index": 104
"kerning": 0

// Layout Info.
"hori_advance": 0
"vert_advance": 0
"x_offset": 640
"y_offset": 1600

// Placement
"MarkAnchor": [
        3,
        {
          "x": 135,
          "y": 250
        },
        {
          "x": 225,
          "y": 0
        }
    ]
}

This is the **computed** x position for each glyph — 5 glyphs
[-438, -2184, -1429, -1454, -1544] // negative for RTL
fn( i ) => -( hor_advance_sum( i ) - x_offset[ i ])

The hori_advance for each glyph from allsorts
[438, 1746, 0, 0, 0]

The x_offset for each glyph from allsorts
[0, 0, 755, 730, 640]

// Render Settings
font_size: 72
dpi: 96
upm: 2048
font: uthmanic_hafs_v20.ttf

I will attach the data collected from allsorts in the next comment.
Looking forward to hearing from you.

[solomancode]

Let me know if you need more details

// Glyphs: result after shaping
[
  {
    "glyph": {
      "raw_glyph": {
        "unicodes": [
          "ٱ"
        ],
        "glyph_index": 139,
        "liga_component_pos": 0,
        "glyph_origin": {
          "Char": "ٱ"
        },
        "small_caps": false,
        "multi_subst_dup": false,
        "is_vert_alt": false,
        "fake_bold": false,
        "fake_italic": false,
        "variation": "VS15"
      },
      "kerning": 0,
      "placement": {
        "None": true
      }
    },
    "position": {
      "hori_advance": 438,
      "vert_advance": 0,
      "x_offset": 0,
      "y_offset": 0
    }
  },
  {
    "glyph": {
      "raw_glyph": {
        "unicodes": [
          "ل"
        ],
        "glyph_index": 300,
        "liga_component_pos": 0,
        "glyph_origin": "Direct",
        "small_caps": false,
        "multi_subst_dup": false,
        "is_vert_alt": false,
        "fake_bold": false,
        "fake_italic": false,
        "variation": "VS15"
      },
      "kerning": 0,
      "placement": {
        "None": true
      }
    },
    "position": {
      "hori_advance": 1746,
      "vert_advance": 0,
      "x_offset": 0,
      "y_offset": 0
    }
  },
  {
    "glyph": {
      "raw_glyph": {
        "unicodes": [
          "ّ"
        ],
        "glyph_index": 107,
        "liga_component_pos": 1,
        "glyph_origin": {
          "Char": "ّ"
        },
        "small_caps": false,
        "multi_subst_dup": false,
        "is_vert_alt": false,
        "fake_bold": false,
        "fake_italic": false,
        "variation": "VS15"
      },
      "kerning": 0,
      "placement": {
        "MarkAnchor": [
          1,
          {
            "x": 970,
            "y": 1025
          },
          {
            "x": 215,
            "y": -25
          }
        ]
      }
    },
    "position": {
      "hori_advance": 0,
      "vert_advance": 0,
      "x_offset": 755,
      "y_offset": 1050
    }
  },
  {
    "glyph": {
      "raw_glyph": {
        "unicodes": [
          "َ"
        ],
        "glyph_index": 104,
        "liga_component_pos": 1,
        "glyph_origin": {
          "Char": "َ"
        },
        "small_caps": false,
        "multi_subst_dup": false,
        "is_vert_alt": false,
        "fake_bold": false,
        "fake_italic": false,
        "variation": "VS15"
      },
      "kerning": 0,
      "placement": {
        "MarkAnchor": [
          2,
          {
            "x": 200,
            "y": 300
          },
          {
            "x": 225,
            "y": 0
          }
        ]
      }
    },
    "position": {
      "hori_advance": 0,
      "vert_advance": 0,
      "x_offset": 730,
      "y_offset": 1350
    }
  },
  {
    "glyph": {
      "raw_glyph": {
        "unicodes": [
          "َ"
        ],
        "glyph_index": 104,
        "liga_component_pos": 2,
        "glyph_origin": {
          "Char": "َ"
        },
        "small_caps": false,
        "multi_subst_dup": false,
        "is_vert_alt": false,
        "fake_bold": false,
        "fake_italic": false,
        "variation": "VS15"
      },
      "kerning": 0,
      "placement": {
        "MarkAnchor": [
          3,
          {
            "x": 135,
            "y": 250
          },
          {
            "x": 225,
            "y": 0
          }
        ]
      }
    },
    "position": {
      "hori_advance": 0,
      "vert_advance": 0,
      "x_offset": 640,
      "y_offset": 1600
    }
  }
]

[wezm]

I can reproduce this with allsorts view -f uthmanic_hafs_v22.ttf -s arab -t ٱللَّهَ" > example.svg as well as in Prince so it looks like it might be a bug and not anything to do with how you're using allsorts. I'll see what I can work out.

[wezm]

Just noting here that this was fixed in 0.14.2.

[solomancore]

Thank you @wezm :)

[solomancode]

@wezm Thank you so much for always being so responsive. If there’s ever anything I can help you with, please don’t hesitate to let me know. I'd love to contribute to allsorts development but I'm not very familiar with the source code, If you can work out a solution I'd love to implement it.

Have a good day.