{"resolved":true,"match_type":"uuid","source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","requested_by":"printed_page","book":{"source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","id":"38270854-596f-4a26-8183-db8c968c6020","uuid":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","normalized_title":"编码隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","isbns":["9787121181184","0123456789","6044921875","3039331000","0000000000","0000000000000"],"parsed":true,"ai_readable":true,"document_type":"book","page_count":438,"navigation_url":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020","title_url":"https://workshop.closeclaw.top/ai/title/%E7%BC%96%E7%A0%81%20%E9%9A%90%E5%8C%BF%E5%9C%A8%E8%AE%A1%E7%AE%97%E6%9C%BA%E8%BD%AF%E7%A1%AC%E4%BB%B6%E8%83%8C%E5%90%8E%E7%9A%84%E8%AF%AD%E8%A8%80","fixed_page_url_template":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","path_api_url_template":"https://workshop.closeclaw.top/api/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","read_url":"https://workshop.closeclaw.top/api/ai/read/38270854-596f-4a26-8183-db8c968c6020","page_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/page","search_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/search"},"page":{"printed_page":403,"pdf_page":419,"physical_index":419,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"efc51c63b30951e3dbe180ceec3225c106cf217b72fbc77d6802013e5dc923ea"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"这种方案可能只适合简单的类似卡通画的图像。真实世界出现的几乎所有颜色都是由红、绿、蓝三原色的不同色阶（levels）组合而成的。如果为每个像素赋予2个字节的存储空间，这样一来，可以给每一个原色分配5位（1位保留）存储空间，这种方法可以表示出红、绿、蓝三种颜色且每种颜色具备32种不同的色阶，这样算下来总共有32,768种不同的颜色。这种模式通常称做高彩色(high color)或数干种颜色(thousands of colors)。\n\n我们下面尝试一下用3个字节来表示一个像素，三原色中的每一种各占一个字节。这种编码模式使红、绿、蓝各自呈现出256种不同的色阶，这样算下来共有16,777,216种不同的颜色，这种方案通常叫做全彩色（full color）或百万种颜色（millions of colors)。如果视频显示器的分辨率为640×480，即水平640像素，垂直480像素，将像素点的数量乘以表示每个像素点需要的字节数可以得到，共需要921,600字节的存储容量，即将近1MB。\n\n每个像素所赋予的比特数有时也称做色深（colordepth）或色彩分辨率（colorresolution)。颜色数与单个像素被赋予的比特数的关系如下：\n\n$$\n3 ) \\textcircled { 1 } Z � s t 3 = 2 ^ { 2 }\n$$\n\n如果视频适配卡配备的存储器容量有限，那么它的最大色深或色彩分辨率自然而然也受到约束。假设有一个配备了1MB存储器的视频适配卡，在每个像素被赋予3个字节的情况下分辨率可以达到640×480。如果想把分辨率提高到800×600，存储器就不足以为每个像素赋予3个字节，必须缩减到用2个字节来表示一个像素。\n\n虽然现在来看在显示器上使用光栅技术似乎是很自然的事情，但是在早期，这种做法并不可行，因为在当时看来，这种技术需要的存储器空间太大。在这种情况下SAGE视频显示器应运而生，它是一种矢量（vector）显示器，相比电视机，它更像一种示波器。\n\n25 图形化革命\n\n403","previous_page":402,"next_page":404}