{"id":128,"date":"2024-08-16T17:21:25","date_gmt":"2024-08-16T17:21:25","guid":{"rendered":"https:\/\/www.mickiwiki.com\/?p=128"},"modified":"2025-03-25T13:02:28","modified_gmt":"2025-03-25T13:02:28","slug":"centres","status":"publish","type":"post","link":"https:\/\/www.mickiwiki.com\/?p=128","title":{"rendered":"Centres"},"content":{"rendered":"\n

Change the co-ordinates of an overlay FROM its centre relative to canvas centre TO its top left corner relative to canvas top left corner (0,0)
W= canvas width
H= canvas height
w= overlay width
h = overlay height
cx = overlay centre x relative to canvas centre x
( left of canvas centre cx is negative, right of canvas centre cx is positive )
cy = overlay centre y relative to canvas centre y
( above canvas centre cy is negative, below canvas centre cy is positive )
<\/p>\n\n\n\n

Position of top left corner of overlay relative to top left corner of canvas is;
x=((W-w)\/2)+cx
y=((H-h)\/2)+cy<\/p>\n\n\n\n

This is probably useful if you want to place images. If you calculate from their centres it doesn’t matter how big the images are.<\/p>\n\n\n\n

use Image::Imlib2;\nmy ($x,$y,$x1,$y1,$w,$h,$canw,$canh);\n$canw=400;\n$canh=400;\nmy $image0=Image::Imlib2->new($canw,$canh);\n$image0->has_alpha(255);\n$x=-100;\n$y=-100;\n$w=100;###<<<<\n$h=100;###<<<<\n$x1=(($canw-$w)\/2)+$x;\n$y1=(($canh-$h)\/2)+$y;\n$image0->set_color(0,0,255,100);#blue\n$image0->fill_rectangle($x1,$y1,$w,$h);\n\n$x=-100;\n$y=-100;\n$w=200;###<<<<\n$h=200;###<<<<\n$x1=(($canw-$w)\/2)+$x;\n$y1=(($canh-$h)\/2)+$y;\n$image0->set_color(255,0,0,100);#red\n$image0->fill_rectangle($x1,$y1,$w,$h);\n\n$image0->save('rectangle3.png');<\/code><\/pre>\n\n\n\n
\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"
Change the co-ordinates of an overlay FROM its centre relative to canvas centre TO its top left corner relative to canvas top left corner (0,0)W= canvas widthH= canvas heightw= overlay widthh = overlay heightcx = overlay centre x relative to canvas centre x( left of canvas centre cx is negative, right of canvas centre cx… Centres<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-128","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/posts\/128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=128"}],"version-history":[{"count":3,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/posts\/128\/revisions"}],"predecessor-version":[{"id":215,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=\/wp\/v2\/posts\/128\/revisions\/215"}],"wp:attachment":[{"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mickiwiki.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}