{"id":5174,"date":"2020-01-18T12:05:26","date_gmt":"2020-01-18T04:05:26","guid":{"rendered":"http:\/\/blog.qdac.cc\/?p=5174"},"modified":"2020-01-18T12:05:27","modified_gmt":"2020-01-18T04:05:27","slug":"%e6%95%99%e7%a8%8b-delphi-%e4%b8%ad-tjpegimage-%e4%b8%ad%e7%9a%84%e4%b8%80%e5%a4%84%e9%97%ae%e9%a2%98%e4%bf%ae%e5%a4%8d","status":"publish","type":"post","link":"https:\/\/blog.qdac.cc\/?p=5174","title":{"rendered":"[\u6559\u7a0b] Delphi \u4e2d TJpegImage \u4e2d\u7684\u4e00\u5904\u95ee\u9898\u4fee\u590d"},"content":{"rendered":"\n

Delphi \u4e2d\u68c0\u6d4b JPEG \u56fe\u7247\u683c\u5f0f\u6d41\u7684\u539f\u59cb\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n\n\n\n

class function TJPEGImage.CanLoadFromStream(Stream: TStream): Boolean;\nvar\n  soi, marker: Word;\n  P: Int64;\nbegin\n  P := Stream.Position;\n  try\n    Result := (Stream.Read(soi, SizeOf(soi)) = SizeOf(soi)) and (soi = $D8FF) and\n      (Stream.Read(marker, SizeOf(marker)) = SizeOf(marker)) and (marker and $E0FF = $E0FF);\n  finally\n    Stream.Position := P;\n  end;\nend;<\/code><\/pre>\n\n\n\n
\u540c\u65f6\u68c0\u67e5\u4e86 soi \u548c marker\uff0c\u4f46\u662f marker \u7684\u503c\u5b9e\u9645\u4e0a\u662f\u6ca1\u6709\u4fdd\u8bc1\u7684\u3002\u6240\u4ee5\u6b63\u786e\u7684\u505a\u6cd5\u662f\u53bb\u6389\u5bf9 marker \u7684\u68c0\u67e5\u3002\u4fee\u6b63\u540e\u7684\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n\n\n\n
class function TJPEGImage.CanLoadFromStream(Stream: TStream): Boolean;\nvar\n  soi, marker: Word;\n  P: Int64;\nbegin\n  P := Stream.Position;\n  try\n    Result := (Stream.Read(soi, SizeOf(soi)) = SizeOf(soi)) and (soi = $D8FF);\n  finally\n    Stream.Position := P;\n  end;\nend;<\/code><\/pre>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Delphi \u4e2d\u68c0\u6d4b JPEG \u56fe\u7247\u683c\u5f0f […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[69,8],"tags":[778,653,23],"class_list":["post-5174","post","type-post","status-publish","format-standard","hentry","category-c-builder","category-delphi","tag-jpeg","tag-653","tag-23"],"views":3697,"_links":{"self":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/5174","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5174"}],"version-history":[{"count":1,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/5174\/revisions"}],"predecessor-version":[{"id":5175,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/5174\/revisions\/5175"}],"wp:attachment":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}