控制虚拟机中Linux文本终端屏幕分辨率

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8 月 052021
 

通过查看dmesg信息获取当前文本终端的默认显示分辨率

[ 4.426948] [drm] DMA map mode: Caching DMA mappings.
[ 4.427281] [drm] Capabilities:
[ 4.427282] [drm] Rect copy.
[ 4.427282] [drm] Cursor.
[ 4.427283] [drm] Cursor bypass.
[ 4.427283] [drm] Cursor bypass 2.
[ 4.427283] [drm] 8bit emulation.
[ 4.427284] [drm] Alpha cursor.
[ 4.427284] [drm] 3D.
[ 4.427284] [drm] Extended Fifo.
[ 4.427284] [drm] Multimon.
[ 4.427285] [drm] Pitchlock.
[ 4.427285] [drm] Irq mask.
[ 4.427285] [drm] Display Topology.
[ 4.427286] [drm] GMR.
[ 4.427286] [drm] Traces.
[ 4.427286] [drm] GMR2.
[ 4.427286] [drm] Screen Object 2.
[ 4.427287] [drm] Command Buffers.
[ 4.427287] [drm] Command Buffers 2.
[ 4.427287] [drm] Guest Backed Resources.
[ 4.427288] [drm] DX Features.
[ 4.427288] [drm] HP Command Queue.
[ 4.427288] [drm] Capabilities2:
[ 4.427289] [drm] Grow oTable.
[ 4.427289] [drm] IntraSurface copy.
[ 4.427289] [drm] DX3.
[ 4.427290] [drm] Max GMR ids is 64
[ 4.427291] [drm] Max number of GMR pages is 65536
[ 4.427292] [drm] Max dedicated hypervisor surface memory is 0 kiB
[ 4.427292] [drm] Maximum display memory size is 262144 kiB
[ 4.427293] [drm] VRAM at 0xe8000000 size is 131072 kiB
[ 4.427294] [drm] MMIO at 0xfe000000 size is 256 kiB
[ 4.437927] [TTM] Zone kernel: Available graphics memory: 996108 KiB
[ 4.464121] [drm] Screen Target Display device initialized
[ 4.464193] [drm] width 1280
[ 4.464211] [drm] height 768
[ 4.464229] [drm] bpp 32
[ 4.493584] [drm] Fifo max 0x00040000 min 0x00001000 cap 0x0000077f
[ 4.591064] [drm] Using command buffers with DMA pool.
[ 4.594738] [drm] Atomic: yes.
[ 4.594741] [drm] SM5 support available.

通过hwinfo命令查看当前可用的分辨率模式

[root@fedora ~]# hwinfo --framebuffer
02: None 00.0: 11001 VESA Framebuffer 
[Created at bios.459]
Unique ID: rdCR.O3PgoQaqFo1
Hardware Class: framebuffer
Model: "VMware virtual machine"
Vendor: "VMware, Inc"
Device: "VMware virtual machine"
SubVendor: "V M ware, Inc. VBE support 2.0"
SubDevice: 
Revision: "2.0"
Memory Size: 0 MB
Memory Range: 0xe8000000-??? (rw)
Mode 0x0300: 640x400 (+640), 8 bits
Mode 0x0301: 640x480 (+640), 8 bits
Mode 0x0303: 800x600 (+800), 8 bits
Mode 0x0305: 1024x768 (+1024), 8 bits
Mode 0x0307: 1280x1024 (+1280), 8 bits
Mode 0x030e: 320x200 (+640), 16 bits
Mode 0x0311: 640x480 (+1280), 16 bits
Mode 0x0314: 800x600 (+1600), 16 bits
Mode 0x0317: 1024x768 (+2048), 16 bits
Mode 0x031a: 1280x1024 (+2560), 16 bits
Mode 0x0320: 320x200 (+320), 8 bits
Mode 0x0321: 320x400 (+320), 8 bits
Mode 0x0322: 640x400 (+640), 8 bits
Mode 0x0323: 640x480 (+640), 8 bits
Mode 0x0324: 800x600 (+800), 8 bits
Mode 0x0325: 1024x768 (+1024), 8 bits
Mode 0x0326: 1152x864 (+1152), 8 bits
Mode 0x0327: 1280x960 (+1280), 8 bits
Mode 0x0328: 1280x1024 (+1280), 8 bits
Mode 0x0329: 1400x1050 (+1408), 8 bits
Mode 0x032a: 1600x1200 (+1600), 8 bits
Mode 0x032b: 1792x1344 (+1792), 8 bits
Mode 0x032c: 1856x1392 (+1856), 8 bits
Mode 0x032d: 1920x1440 (+1920), 8 bits
Mode 0x032e: 320x200 (+640), 16 bits
Mode 0x032f: 320x400 (+640), 16 bits
Mode 0x0330: 640x400 (+1280), 16 bits
Mode 0x0331: 640x480 (+1280), 16 bits
Mode 0x0332: 800x600 (+1600), 16 bits
Mode 0x0333: 1024x768 (+2048), 16 bits
Mode 0x0334: 1152x864 (+2304), 16 bits
Mode 0x0335: 1280x960 (+2560), 16 bits
Mode 0x0336: 1280x1024 (+2560), 16 bits
Mode 0x0337: 1400x1050 (+2816), 16 bits
Mode 0x0338: 1600x1200 (+3200), 16 bits
Mode 0x0339: 1792x1344 (+3584), 16 bits
Mode 0x033a: 1856x1392 (+3712), 16 bits
Mode 0x033b: 1920x1440 (+3840), 16 bits
Mode 0x033c: 320x200 (+1280), 24 bits
Mode 0x033d: 320x400 (+1280), 24 bits
Mode 0x033e: 640x400 (+2560), 24 bits
Mode 0x033f: 640x480 (+2560), 24 bits
Mode 0x0340: 800x600 (+3200), 24 bits
Mode 0x0341: 1024x768 (+4096), 24 bits
Mode 0x0342: 1152x864 (+4608), 24 bits
Mode 0x0343: 1280x960 (+5120), 24 bits
Mode 0x0344: 1280x1024 (+5120), 24 bits
Mode 0x0345: 1400x1050 (+5600), 24 bits
Mode 0x0346: 1600x1200 (+6400), 24 bits
Mode 0x0347: 1792x1344 (+7168), 24 bits
Mode 0x0348: 1856x1392 (+7424), 24 bits
Mode 0x0349: 1920x1440 (+7680), 24 bits
Mode 0x034a: 1366x768 (+1376), 8 bits
Mode 0x034b: 1366x768 (+2752), 16 bits
Mode 0x034c: 1366x768 (+5472), 24 bits
Mode 0x034d: 1680x1050 (+1696), 8 bits
Mode 0x034e: 1680x1050 (+3360), 16 bits
Mode 0x034f: 1680x1050 (+6720), 24 bits
Mode 0x0350: 1920x1200 (+1920), 8 bits
Mode 0x0351: 1920x1200 (+3840), 16 bits
Mode 0x0352: 1920x1200 (+7680), 24 bits
Mode 0x0353: 2048x1536 (+2048), 8 bits
Mode 0x0354: 2048x1536 (+4096), 16 bits
Mode 0x0355: 2048x1536 (+8192), 24 bits
Mode 0x0356: 320x240 (+320), 8 bits
Mode 0x0357: 320x240 (+640), 16 bits
Mode 0x0358: 320x240 (+1280), 24 bits
Mode 0x0359: 400x300 (+416), 8 bits
Mode 0x035a: 400x300 (+800), 16 bits
Mode 0x035b: 400x300 (+1600), 24 bits
Mode 0x035c: 512x384 (+512), 8 bits
Mode 0x035d: 512x384 (+1024), 16 bits
Mode 0x035e: 512x384 (+2048), 24 bits
Mode 0x035f: 854x480 (+864), 8 bits
Mode 0x0360: 854x480 (+1728), 16 bits
Mode 0x0361: 854x480 (+3424), 24 bits
Mode 0x0362: 1280x720 (+1280), 8 bits
Mode 0x0363: 1280x720 (+2560), 16 bits
Mode 0x0364: 1280x720 (+5120), 24 bits
Mode 0x0365: 1920x1080 (+1920), 8 bits
Mode 0x0366: 1920x1080 (+3840), 16 bits
Mode 0x0367: 1920x1080 (+7680), 24 bits
Mode 0x0368: 1280x800 (+1280), 8 bits
Mode 0x0369: 1280x800 (+2560), 16 bits
Mode 0x036a: 1280x800 (+5120), 24 bits
Mode 0x036b: 1440x900 (+1440), 8 bits
Mode 0x036c: 1440x900 (+2880), 16 bits
Mode 0x036d: 1440x900 (+5760), 24 bits
Mode 0x036e: 720x480 (+736), 8 bits
Mode 0x036f: 720x480 (+1440), 16 bits
Mode 0x0370: 720x480 (+2880), 24 bits
Mode 0x0371: 720x576 (+736), 8 bits
Mode 0x0372: 720x576 (+1440), 16 bits
Mode 0x0373: 720x576 (+2880), 24 bits
Mode 0x0374: 800x480 (+800), 8 bits
Mode 0x0375: 800x480 (+1600), 16 bits
Mode 0x0376: 800x480 (+3200), 24 bits
Mode 0x0377: 1280x768 (+1280), 8 bits
Mode 0x0378: 1280x768 (+2560), 16 bits
Mode 0x0379: 1280x768 (+5120), 24 bits
Config Status: cfg=new, avail=yes, need=no, active=unknown
[root@fedora ~]#

修改文本终端分辨率模式的三种方法

1）在Linux启动阶段输出可用分辨率模式并由用户选择

vga=ask

2）在Linux启动阶段手动添加分辨率模式参数

vga=0x0364

3）修改GRUB2引导菜单配置，永久新增分辨率模式参数

[root@fedora ~]# grubby --default-kernel
/boot/vmlinuz-5.11.12-300.fc34.x86_64
[root@fedora ~]# grubby --args="vga=0x0364" --update-kernel /boot/vmlinuz-5.11.12-300.fc34.x86_64
[root@fedora ~]#

修改GRUB2引导菜单配置并重启后查看GRUB2引导菜单的变化

查看分辨率为1280*720的虚拟机文本终端窗口

https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/kernel-module-driver-configuration/Working_with_the_GRUB_2_Boot_Loader/#sec-Making_Persistent_Changes_to_a_GRUB_2_Menu_Using_the_grubby_Tool

DPI定义及其对图像分辨率和行业影响

 桌面应用  No Responses »
6 月 012021
  
(10 inches * 128 dpi) * (6 inches * 128 dpi) = 1280 * 768
(8 inches * 128 dpi) * (6 inches * 128 dpi) = 1024 * 768
(10 inches * 128 dpi) * (8 inches * 128 dpi) = 1280 * 1024

What Is DPI and What Are the Requirements for Different Industries?

For businesses investing in printing and scanning resources, it’s important to understand the project requirements. Balancing cost and output, and ensuring the right resources are applied to the requirements, isn’t always easy.

Investing in the wrong technology or services can mean wasted money. Implementing the wrong solution can put your business at risk and leave employees struggling with an inadequate solution.

We’ll look at dots per inch, or DPI, and how businesses can use it to determine the scope and requirements of printing and scanning services. We’ll also look at DPI as a baseline measure for certain industries and requirements, so you can scale and budget your services.

What Is DPI and How Is It Used?

DPI, or dots per inch, is a measure of the resolution of a printed document or digital scan. The higher the dot density, the higher the resolution of the print or scan. Typically, DPI is the measure of the number of dots that can be placed in a line across one inch, or 2.54 centimeters.

The higher the DPI, the sharper the image. A higher resolution image provides the printer and printing device more information. You can get more detail and greater resolution from an image with higher DPI.

A lower DPI will produce an image with fewer dots in printing. No matter how powerful your printer is, a low-resolution image doesn’t provide enough raw data to produce high-quality images. The ink will spread on the page, making the edges look fuzzy.

Similarly, a monitor will measure the pixels per inch, or PPI, of a video display. Typically, a printer must offer a higher DPI to match the color quality and resolution of a video display PPI. This is due to the limited range of colors in a print job.

DPI Printing and Industry Standards

Let’s review a few standards and guidelines for using DPI in printing services. Keep in mind, you’ll need a better, and more capable, printer or print service to deliver higher-quality and high-resolution printing output.

1. Low-Resolution Images

Low-resolution images are considered 150dpi and less. For print, 150dpi is considered low-quality printing, even though 72dpi is considered the standard for the web (which is why it’s not easy printing quality images straight from the web). Low-resolution images will have blurring and pixelation after printing.

For business purposes, low-resolution images are suitable for scanning text documents and storing records digitally. Internal office communication can be reproduced with a low resolution, but anything used outside the office should be higher than 150dpi. After all, the printing quality needs to represent your business.

2. Medium-Resolution Images

Medium-resolution images have between 200dpi-300dpi. The industry standard for quality photographs and image is typically 300dpi.

For businesses, producing an external document like a brochure, a booklet, or a flyer requires 300dpi. You might be able to get away with 250dpi if you are less concerned with the quality and resolution of the printing. Any marketing material or collateral produced should be, at a minimum, 300dpi. Booklets, pamphlets, reports, and sales sheets should all be printed at 250dpi-300dpi or more.

A good rule to follow is when in doubt, select a higher dpi for your material.

3. High-Resolution Images

Most businesses consider 600dpi and higher to be a high-resolution image or print. High-resolution images require more memory to store and can take longer to scan. Storing high-resolution images can quickly fill a hard drive or server. Many desktop printers can’t reproduce high-quality and high-resolution images. Professional print services are often the best solution for high-resolution images.

Keep in mind, there are diminishing returns for increasing the resolution of an image. Any print above 1,200dpi will deliver improvements that are practically unnoticeable to the naked eye. You won’t be able to see any difference between documents. Only professional photographers or artists with highly detailed work will need resolution that high.

Other Factors That Influence Print Quality

DPI isn’t the only factor that determines the resolution and print quality. Often, these other factors can have more impact on quality and resolution.

For example, sometimes users will change the resolution of an image in software like Photoshop. This will increase the DPI, but it won’t change or increase the quality of the image. The pixels in the image are larger, resulting in a pixelated, almost unprintable, image. This is known as upsampling.

The printer, and ink used in the printer, can also affect print output. Laser jet printers use a toner that doesn’t bleed into the paper, producing a crisper image. Inkjet printers will bleed, which can lower the appearance of dots per inch for a printed work.

What Is DPI and What It Means for You

Selecting the right DPI printing services and office technology is important. Dots per inch is one factor that can influence the efficiency and cost of print services. It’s important to identify your business requirements and scanning and printing needs before selecting print services.

What Is DPI and What Are the Requirements for Different Industries? – Donnellon McCarthy (dme.us.com)