BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  TImage in ScrollBox; resize speed prob at wsMaximize          BorlandTalk.com Forum Index -> Delphi Graphics View previous topic :: View next topic   Author Message Klaus Hast Guest Posted: Wed Jul 12, 2006 2:37 am    Post subject: TImage in ScrollBox; resize speed prob at wsMaximize Hi dear experts, I have (D4/Win98 or D6PE/W2K) a TImage on a ScrollBox (ScrollBox DoubleBuffered:=True) presenting a Bitmap received from somewhere kept in a FBitmap variable, where mostly the TImage is alClient aligned to the Scrollbox. The bitmap's load time and normal resize actions are ok. But at doubleclick on the caption bar (-> wsMaximize) i have a noticeable speed delay compared eg. to similar C-Applications (when maximizing the window). --- Without doublebuffer the speed is ok, but i get flicker. With doublebuffer no flicker, but the speed at maximize decreases noticeably. Some tests on FBitmap's fast stretch operations by hand did not have better results. -- Questions to the experts: any proposals to improve the performance of maximize actions on a TImage parented by a ScrollBox? Any hack-arounds the StretchDraw-API within the TImage Bitmap draw or is it the fastest method we can have? Many thanks for advice in advance, Klaus PS: replacing the scrollbox by a paintbox or panel does not have better results. Back to top Finn Tolderlund Guest Posted: Wed Jul 12, 2006 2:44 am    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize "Klaus Hast" <khast (AT) arcor (DOT) de> skrev i en meddelelse news:44b41a58$1 (AT) newsgroups (DOT) borland.com... Quote: Questions to the experts: any proposals to improve the performance of maximize actions on a TImage parented by a ScrollBox? Any hack-arounds the StretchDraw-API within the TImage Bitmap draw or is it the fastest method we can have? How large is the bitmap? Make sure that it's no larger than the screen size. If it is larger, resize it down before putting it into the TImage. That might improve performance. -- Finn Tolderlund http://www.tolderlund.eu/delphi/ Back to top Klaus Hast Guest Posted: Wed Jul 12, 2006 2:51 am    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Hi (and many thanks for reply!), Before the TImage sees the the FBitmap, it is already resized so that it does not exceed the boundaries of the screen. So the issue is not related to a bitmap which is too large regarding width or height. Best Regards! Koaus Quote: How large is the bitmap? Make sure that it's no larger than the screen size. If it is larger, resize it down before putting it into the TImage. That might improve performance. Back to top C-H Guest Posted: Wed Jul 12, 2006 3:05 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize "Klaus Hast" <khast (AT) arcor (DOT) de> wrote: Quote: any proposals to improve the performance of maximize actions on a TImage parented by a ScrollBox? A trick I've used to kill flicker without having to set DoubleBuffered to true is to trap the WM_ERASEBKGND message sent to the control on which the Image or Painbox is placed, and tell the control not to erase its background if it doesn't have to (transparent pictures are problematic). If you have other things on the ScrollBox the best solution would probably be to make a TPanel descendant and place the image on that. Align the Image to Client. You could try installing a component that looks something like this: ----------------------- unit PanelFF; interface uses Windows, Messages, SysUtils, Classes, Controls, Forms, Graphics; type TPanelFF = class(TPanel) private procedure WMEraseBkgnd(var Msg: TWMEraseBkgnd); message WM_ERASEBKGND; public constructor Create(AOwner: TComponent); override; property EraseBG: Boolean read FEraseBg write FEraseBg; end; procedure Register; implementation constructor TPanelFF.Create(AOwner: TComponent); begin inherited Create(AOwner); FEraseBg := True; end; procedure TPanelFF.WMEraseBkgnd(var Msg: TWMEraseBkgnd); begin if not EraseBg then Msg.Result := 1 //don't erase bg else inherited; end; procedure Register; begin RegisterComponents('Samples', [TPanelFF]); end; end. ---------------------- In your app you can then determine if you wan't to erase or not. For instance: if MyPictureIsTransparent then PanelFF1.EraseBg := True else PanelFF1.EraseBg := False; /C-H Back to top Klaus Hast Guest Posted: Wed Jul 12, 2006 9:57 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Hi C-H, i already used the suppression of the WM_ERASEBKGND message, without good results, but however you gave me the good idea ... in fact i need to take care that this trap has to be applied on the parent of the image, so the scrollbox ... So i created a TScrollBox descendant and applied it here ... and that looks promising! --- However that leads to the subsequent question how to repaint the remaining part of the scrollbox which is not covered by the image. --- What i mean is: regarding the size of the image which is proportionally stretched (keeping its aspect ratio) the resized scrollbox is not fully filled by the proportinally resized and centered image (parts of the top/bottom resp. left/right would need to be repainted using the background color by hand). --- So, how to detect and repaint the regions of the scrollbox which are not fully covered by the image? (repaint scrollbox minus DestRect of the Image) Many thanks again, Klaus Quote: A trick I've used to kill flicker without having to set DoubleBuffered to true is to trap the WM_ERASEBKGND message sent to the control on which the Image or Painbox is placed, and tell the control not to erase its background if it doesn't have to (transparent pictures are problematic). If you have other things on the ScrollBox the best solution would probably be to make a TPanel descendant and place the image on that. Align the Image to Client. Back to top Peter Below (TeamB) Guest Posted: Wed Jul 12, 2006 11:31 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Klaus Hast wrote: Quote: Hi dear experts, I have (D4/Win98 or D6PE/W2K) a TImage on a ScrollBox (ScrollBox DoubleBuffered:=True) presenting a Bitmap received from somewhere kept in a FBitmap variable, where mostly the TImage is alClient aligned to the Scrollbox. The bitmap's load time and normal resize actions are ok. But at doubleclick on the caption bar (-> wsMaximize) i have a noticeable speed delay compared eg. to similar C-Applications (when maximizing the window). --- Without doublebuffer the speed is ok, but i get flicker. Ditch the image, use a TPaintbox instead and paint the bitmap in its OnPaint event. This way you control whether the background gets erased or not. Doublebuffering is no longer necessary. -- Peter Below (TeamB) Don't be a vampire (http://slash7.com/pages/vampires), use the newsgroup archives : http://www.tamaracka.com/search.htm http://groups.google.com http://www.prolix.be Back to top Klaus Hast Guest Posted: Thu Jul 13, 2006 12:24 am    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Peter Below (TeamB) <none> schrieb in im Newsbeitrag: xn0eon85z19bsg002 (AT) newsgroups (DOT) borland.com... Quote: Ditch the image, use a TPaintbox instead and paint the bitmap in its OnPaint event. This way you control whether the background gets erased or not. Doublebuffering is no longer necessary. Hello Peter, First, kind thanks for your quick reply! Compared with the paintbox approach do you see any disadvantages when using the (non-doublebufferd) scrollbox approach as described in my reply to C-H within this thread ? (Descendant of TScrollBox [for to suppress wm_erasebkgnd]; TImage herein -> for to have all scrolling and proportional resizing (StretchDraw) capabilities without reinventing the wheel). Is it quite as good in your eyes? If yes: only remaining question: how to detect and repaint the regions of the scrollbox which are not fully covered by a proportionally stretched, and then centered, image (when aspect ratio of the image <> aspect ratio of the scrollbox) ? If no: why? Many thanks, Klaus Back to top C-H Guest Posted: Thu Jul 13, 2006 2:05 am    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize "Klaus Hast" <khast (AT) arcor (DOT) de> wrote: Quote: Hi C-H, --- However that leads to the subsequent question how to repaint the remaining part of the scrollbox which is not covered by the image. --- So, how to detect and repaint the regions of the scrollbox which are not fully covered by the image? (repaint scrollbox minus DestRect of the Image) I understand your problem, but that approach is hard to pull through. You will probably end up getting flicker again from large areas having to be repainted separately. My advise would be to try placing the Image on a Panel and do the sizing operations on the Panel instead of on the Image (keep the Image aligned to client and set streched to true). In my experience trapping the WM_ERASEBKGND message is the only way to control flicker in certain situations. Peter's suggestion is not enough. /C-H Back to top C-H Guest Posted: Thu Jul 13, 2006 2:39 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize "C-H" <blabla (AT) NO_SPAM (DOT) com> wrote: Quote: My advise would be to try placing the Image on a Panel and do the sizing operations on the Panel instead of on the Image. Scrolling performance may suffer though. As we don't know what your app is doing and how you want your picture presented it's difficult to come up with relevant solutions. We're also in a tricky trial-and-error territory here. The question is, why are you getting flicker in the first place? Are you moving the Image to keep it centered at resizing? If so I have no good solution to offer, sorry. /C-H Back to top Peter Below (TeamB) Guest Posted: Thu Jul 13, 2006 11:44 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Klaus Hast wrote: Quote: Compared with the paintbox approach do you see any disadvantages when using the (non-doublebufferd) scrollbox approach as described in my reply to C-H within this thread ? (Descendant of TScrollBox [for to suppress wm_erasebkgnd]; TImage herein -> for to have all scrolling and proportional resizing (StretchDraw) capabilities without reinventing the wheel). Is it quite as good in your eyes? It could certainly be made to work. Quote: If yes: only remaining question: how to detect and repaint the regions of the scrollbox which are not fully covered by a proportionally stretched, and then centered, image (when aspect ratio of the image <> aspect ratio of the scrollbox) ? Build a region from the parts of the scrollboxes visible area that are covered by other controls. Save the state of the canvas.handle (SaveDC), select the region as clipping region into the canvas.handle (SelectClipRgn), then do the standard background fill for the scrollbox. Finally restore the canvas.handle state (RestoreDC). You can also directly paint the bitmap at this point, no need or use for a paintbox or timage. -- Peter Below (TeamB) Don't be a vampire (http://slash7.com/pages/vampires), use the newsgroup archives : http://www.tamaracka.com/search.htm http://groups.google.com http://www.prolix.be Back to top Klaus Hast Guest Posted: Fri Jul 14, 2006 1:20 am    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Hello Peter, thank you for all those responses! I try to test with this proposal. Meanwhile i got the following construct to work too quite sufficiently (at least better than before): * Form (for to keep scrolling capabilities:) * Non-doublebuffered Scrollbox descendant which supresses erase_background (for to keep proportional scaling and centering capabilities:) * A TImage clone (base on TGrapiccontrol) which does a corrective action before the StretchDraw: if DestRect.top > 0 then canvas.FillRect(Rect(0, 0, width, DestRect.top-1)); if DestRect.bottom < height then canvas.FillRect(Rect(0, DestRect.bottom+1, width, height)); if DestRect.left > 0 then canvas.FillRect(Rect(0, 0, DestRect.left, height)); if DestRect.right < width then canvas.FillRect(Rect(DestRect.right+1, 0, width, height)); canvas.stretchdraw(DestRect, picture.graphic); Is that be ok in your eyes, basically, or simply a bad hack? Best Regards, Klaus Back to top Peter Below (TeamB) Guest Posted: Fri Jul 14, 2006 11:43 pm    Post subject: Re: TImage in ScrollBox; resize speed prob at wsMaximize Klaus Hast wrote: Quote: Hello Peter, thank you for all those responses! I try to test with this proposal. Meanwhile i got the following construct to work too quite sufficiently (at least better than before): -snip- Is that be ok in your eyes, basically, or simply a bad hack? That's no hack, that's a tweak <g>. And a decent one, IMO. -- Peter Below (TeamB) Don't be a vampire (http://slash7.com/pages/vampires), use the newsgroup archives : http://www.tamaracka.com/search.htm http://groups.google.com http://www.prolix.be Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Graphics All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.