Display of bold characters unreadable

Bắt đầu bằng cách tái hiện vấn đề trong Xreader 2.2.3 với một PDF sử dụng các phông chữ Custom-Metrics-24 được báo cáo, rồi so sánh cách hiển thị chữ đậm của tệp đó với cùng tệp trong Foxit Reader. Không có tệp nguồn hoặc bài kiểm thử nào được nêu; công việc được xem là hoàn tất khi các ký tự đậm bị ảnh hưởng vẫn dễ đọc trong khi vẫn giữ dạng đậm, và hành vi được xác minh trên các biến thể PDF đã mô tả.

 * Xreader version 2.2.3
 * Distribution - Mint Cinnamon 19.2 LTS, Linux kernel 4.15.0-123-lowlatency.

Issue
Display of bold characters is nearly unreadable in a bank produced PDF report. Bold style makes the characters blurry and character lines are too big which hides white space. For example, a character 6 and a character 8 have no white space in the circle that make the characters.

Verified multiple PDF files.

1. Many PDF files with the problem had the following characteristics, from XReader "File | Properties" menu:
   a. Producer = 303l AIX (64bit)
   b. Creator = Ricoh Production Print Solutions Afp2Pdf Version: 303l
   c. Format = PDF-1.3
   d. Optimized = No
   e. Security = No
   f. Fonts = Custom-Metrics-24; and others. --> NOTE: a previous bank report with "Custom-Metrics-23" instead of "Custom-Metrics-24" displays well.

Other bank reports with the same combination of Producer, Creator, Format, Security, and Optimized values display well. Others with Optimized = Yes also display well. However, the fonts differ.

2. One PDF file with the problem had the following characteristics, from XReader "File | Properties" menu:
   a. Producer = Ricoh Americas Corporation, AFP2PDF Plus Version: 1.200.21, AIX
   b. Creator = Ricoh Americas Corporation, AFP2PDF Plus Version: 1.200.21
   c. Format = PDF-1.4
   d. Optimized = Yes
   e. Security = No
   f. Fonts = Custom-Metrics-24; and others. --> NOTE: Other bank reports with mainly "C0EX0....afm" fonts instead of a combination of different fonts ("C0A....afm", "C0D....afm", and other) display well.

Other bank reports with the same combination of Producer, Creator, Format, Security, and Optimized values display well. However, the fonts differ.

Steps to reproduce
Open a PDF file with the characteristics described above from Nemo file manager, using default XReader.

Expected behaviour
Bold characters should be readable.

Other information
a. Bold characters in the same PDF files are very readable, as expected, while remaining bold using Foxit Reader version 9.72 on a Windows 7 computer.
b. Bold characters in other reports from the same bank display correctly, format "PDF-1.4", Producer = "iText® 5.4.3 ©2000-2013 1T3XT BVBA (AGPL-version)" OR "iText® 5.4.1 ©2000-2012 1T3XT BVBA (AGPL-version)".