使用wxWidgets for C++从资源文件中静态装载图像

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    在wxWidgets中装载图像是非常容易的，但是如果将图像文件和可执行文件放到一起，在发布时只需要发布可执行文件，要实现这种功能，一般可以使用资 源文件来解决。在windows下的资源文件的源文件是*.rc，编译后叫*.res。在linux下类似，源文件为*.xrc，编译后叫*.xres。 但它们是xml格式的，要装载这种资源文件也得动态进行装载。相当于配置文件。

    如果想将其直接编译进可执行文件。需要一个工具wxrc。这个工作在wxWidgets中的untils目录中，可自己编译。可使用这个工具将*.xrc 生成c++代码，如果是图像，就将其转换成字符数组。然后和其它程序一起进行编译。可使用wxrc -c main.xrc -v -o main.h

main.xrc的格式如下：

<?xml version="1.0"?> 
<resource version="2.3.0.1">    
   <object class="wxBitmap" name="background">background.jpg</object> 
</resource>

生成的main.h的格式如下：

//
// This file was automatically generated by wxrc, do not edit by hand.
//

#include <wx/wxprec.h>

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#include <wx/filesys.h>
#include <wx/fs_mem.h>
#include <wx/xrc/xmlres.h>
#include <wx/xrc/xh_all.h>

static size_t xml_res_size_0 = 55966;
static unsigned char xml_res_file_0[] = {
255,216,255,224,0,16,74,70,73,70,0,1,2,0,0,100,0,100,0,0,255,236,0,17,68,
117,99,107,121,0,1,0,4,0,0,0,60,0,0,255,238,0,14,65,100,111,98,101,0,100,
192,0,0,0,1,255,219,0,132,0,6,4,4,4,5,4,6,5,5,6,9,6,5,6,9,11,8,6,6,8,11,
12,10,10,11,10,10,12,16,12,12,12,12,12,12,16,12,14,15,16,15,14,12,19,19,
20,20,19,19,28,27,27,27,28,31,31,31,31,31,31,31,31,31,31,1,7,7,7,13,12,
13,24,16,16,24,26,21,17,21,26,31,31,31,31,31,31,31,31,31,31,31,31,31,31,
31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,
31,31,31,31,31,31,31,31,31,31,31,255,192,0,17,8,2,201,3,248,3,1,17,0,2,
.
.
102,222,191,202,130,94,195,45,21,39,169,149,113,241,11,45,173,84,25,120,
94,18,190,190,196,107,2,216,129,52,90,4,128,1,130,160,201,16,36,0,147,0,
84,68,164,164,47,80,44,0,96,168,202,0,201,145,130,178,49,229,32,127,255,
217};

static size_t xml_res_size_1 = 161;
static unsigned char xml_res_file_1[] = {
60,63,120,109,108,32,118,101,114,115,105,111,110,61,34,49,46,48,34,32,101,
110,99,111,100,105,110,103,61,34,85,84,70,45,56,34,63,62,10,60,114,101,
115,111,117,114,99,101,32,118,101,114,115,105,111,110,61,34,50,46,51,46,
48,46,49,34,62,10,32,32,60,111,98,106,101,99,116,32,99,108,97,115,115,61,
34,119,120,66,105,116,109,97,112,34,32,110,97,109,101,61,34,98,97,99,107,
103,114,111,117,110,100,34,62,114,101,115,111,117,114,99,101,115,46,104,
36,98,97,99,107,103,114,111,117,110,100,46,106,112,103,60,47,111,98,106,
101,99,116,62,10,60,47,114,101,115,111,117,114,99,101,62,10};

void InitXmlResource()
{

    // Check for memory FS. If not present, load the handler:
    {
        wxMemoryFSHandler::AddFile(wxT("XRC_resource/dummy_file"), wxT("dummy one"));
        wxFileSystem fsys;
        wxFSFile *f = fsys.OpenFile(wxT("memory:XRC_resource/dummy_file"));
        wxMemoryFSHandler::RemoveFile(wxT("XRC_resource/dummy_file"));
        if (f) delete f;
        else wxFileSystem::AddHandler(new wxMemoryFSHandler);
    }

    wxMemoryFSHandler::AddFile(wxT("XRC_resource/resources.h$background.jpg"), xml_res_file_0, xml_res_size_0);
    wxMemoryFSHandler::AddFile(wxT("XRC_resource/resources.h$main.xrc"), xml_res_file_1, xml_res_size_1);
    wxXmlResource::Get()->Load(wxT("memory:XRC_resource/resources.h$main.xrc"));
}

其后在主程序中调用 InitXmlResource函数。

要想装载这个background.jpg图，使用以下语句：

    wxXmlResource::Get()->InitAllHandlers();     

wxBitmap background = wxXmlResource::Get()->LoadBitmap(_T("background"));     

m_pStaticBitmap = new wxStaticBitmap(this, wxID_ANY, background, wxPoint(0, 0), wxSize(1024, 768)); 

但要注意使用wxStaticBitmap时应在wxFrame中的OnSize中加入

    m_pStaticBitmap->Refresh();

否则在windows下当窗口缩小后再放大时，图像显示有一些问题。但在linux下可以不加这条语句。