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<HTML><LINK HREF="style.css" REL="STYLESHEET" TYPE="text/css"><HEAD><TITLE>Text and Fonts</TITLE></HEAD><BODY><FONT SIZE="-1">[ <A HREF="./index.html">contents</A>| <A HREF="http://www.winprog.org/">#winprog</A>]</FONT><HR><H1>Text and Fonts</H1><P>Example: font_one</P><IMG SRC="images/font_one.gif" ALT="[images/font_one.gif]" ALIGN="right"><H2>Loading Fonts</H2>The Win32 GDI has some remarkable capabilites for dealing with vastly different typefaces,styles, languages and characters sets. One of the drawbacks of this is that dealing withfonts can look rather intimidating to the newcomer. <CODE>CreateFont()</CODE>, the primaryAPI when it comes to fonts, has 14 parameters for specifying height, style, weight, family,and various other attributes.<P>Fortunately, it's not really has hard as it might appear, and a large portion of the workinvolved is taken care of my sensible default values. All but 2 of the parameters to <CODE>CreateFont()</CODE> can be set to <CODE>0</CODE> or <CODE>NULL</CODE>, and the systemwill simply use a default value giving you a plain ordinary font.<P><CODE>CreateFont()</CODE> creates an <CODE>HFONT</CODE>, a handle to a <I>Logical Font</I> in memory. The data held by this handle can be retreived into a <CODE>LOGFONT</CODE> structure using <CODE>GetObject()</CODE> justas a <CODE>BITMAP</CODE> struct can be filled from an <CODE>HBITMAP</CODE>. <P>The members of the <CODE>LOGFONT</CODE> are identical to the parameters to <CODE>CreateFont()</CODE> andfor convenience you can create a font directly from an existing <CODE>LOGFONT</CODE> structureusing <CODE>CreateFontIndirect()</CODE>.This is very handy, since it makes it simple to create a new font from an existing font handlewhen you only want to alter certain aspects of it. Use <CODE>GetObject()</CODE> to fill a <CODE>LOGFONT</CODE>,alter the members that you wish, and create a new font with <CODE>CreateFontIndirect()</CODE>.<PRE CLASS="SNIP"> HFONT hf; HDC hdc; long lfHeight; hdc = GetDC(NULL); lfHeight = -MulDiv(12, GetDeviceCaps(hdc, LOGPIXELSY), 72); ReleaseDC(NULL, hdc); hf = CreateFont(lfHeight, 0, 0, 0, 0, TRUE, 0, 0, 0, 0, 0, 0, 0, "Times New Roman"); if(hf) { DeleteObject(g_hfFont); g_hfFont = hf; } else { MessageBox(hwnd, "Font creation failed!", "Error", MB_OK | MB_ICONEXCLAMATION); } </PRE><P>This is the code used to create the font in the example image. This is <I>Times New Roman</I> at <I>12 Point</I> withthe <I>Italics</I> style set. The italics flag is the 6th parameter to <CODE>CreateFont()</CODE> which you can see we have set to <CODE>TRUE</CODE>. The name of the font we want to use is the last parameter.<P>The one bit of trickery in this code is the value used for the size of the font, the <CODE>lfHeight</CODE> parameter to <CODE>CreateFont()</CODE>. Usually people are used to working with <I>Point</I> sizes, Size 10, Size 12, etc... when dealing with fonts. <CODE>CreateFont()</CODE> however doesn't accept point sizes, it wants <CODE>Logical Units</CODE>which are different on your screen than they are on your Printer, and even between Printers and screens. <P>The reasonthis situation exists is because the resolution of different devices is so vastly different... Printers can easilydisplay 600 to 1200 pixels per inch, while a screen is lucky to get 200... if you used the same sized font on a printeras on a screen, you likely wouldn't even be able to see individual letters.<P>All we have to do is convert from the point size we want, into the appropriate logical size for the device. In thiscase the device is the screen, so we get the <CODE>HDC</CODE> to the screen, and get the number of logical pixels per inchusing <CODE>GetDeviceCaps()</CODE> and slap this into the formula so generously provided in MSDN which uses <CODE>MulDiv()</CODE> to convert from our pointsize of <CODE>12</CODE> to the correct logical size that <CODE>CreateFont()</CODE>expects. We store this in <CODE>lfHeight</CODE> and pass it as the first parameter to <CODE>CreateFont()</CODE>.<H3>Default Fonts</H3>When you first call <CODE>GetDC()</CODE> to get the <CODE>HDC</CODE> to your window, thedefault font that is selected into it is <I>System</I>, which to be honest isn't all thatattractive. The simplest way to get a reasonable looking font to work with (without going through the <CODE>CreateFont()</CODE>hassle) is to call <CODE>GetStockObject()</CODE> and ask for the <CODE>DEFAULT_GUI_FONT</CODE>. <P>This isa system object and you can get it as many times as you want without leaking memory,and you can call <CODE>DeleteObject()</CODE> on it which won't do anything, which is goodbecause now you don't need to keep track of whether your font is one from <CODE>CreateFont()</CODE> or<CODE>GetStockObject()</CODE> before trying to free it.<H2>Drawing Text</H2>Now that we have a handy-dandy font, how do we get some text on the screen? This is assuming that we don'tjust want to use an Edit or Static control.<P>Your basic options are <CODE>TextOut()</CODE> and <CODE>DrawText()</CODE>. <CODE>TextOut()</CODE> is simpler,but has less options and doesn't do word wrapping or alignment for you.<PRE CLASS="SNIP"> char szSize[100]; char szTitle[] = "These are the dimensions of your client area:"; HFONT hfOld = SelectObject(hdc, hf); SetBkColor(hdc, g_rgbBackground); SetTextColor(hdc, g_rgbText); if(g_bOpaque) { SetBkMode(hdc, OPAQUE); } else { SetBkMode(hdc, TRANSPARENT); } DrawText(hdc, szTitle, -1, prc, DT_WORDBREAK); wsprintf(szSize, "{%d, %d, %d, %d}", prc->left, prc->top, prc->right, prc->bottom); DrawText(hdc, szSize, -1, prc, DT_SINGLELINE | DT_CENTER | DT_VCENTER); SelectObject(hdc, hfOld);</PRE><P>First thing we do is use <CODE>SelectObject()</CODE> to get the font we want to use into our <CODE>HDC</CODE> and ready for drawing. All future text operations will use this font untill another one is selected in.<P>Next we set the Text and Background colours. Setting the background colour doesn't actually make the <I>whole</I>background this colour, it only affects certain operations (text being one of them) that use the background colour todraw with. This is also dependant on the current <I>Background Mode</I>. If it is set to <CODE>OPAQUE</CODE> (the default)then any text drawn is filled in behing with the background colour. If it is set to <CODE>TRANSPARENT</CODE> thentext is drawn without a background and whatever is behind will show through and in this case the background colourhas no effect.<P>Now we actually draw the text using <CODE>DrawText()</CODE>, we pass in the <CODE>HDC</CODE> to use and the stringto draw. The 3rd parameter is the length of the string, but we've passed -1 because <CODE>DrawText()</CODE> issmart enough that it will figure out how long the text is itself. In the 4th parameter we pass in <CODE>prc</CODE>,the pointer to the client <CODE>RECT</CODE>. <CODE>DrawText()</CODE> will draw inside this rectangle based onthe other flags that you give it.<P>In the first call, we specify <CODE>DT_WORDBREAK</CODE>, which defaults to aligned to the top left, and willwrap the text it draws automatically at the edge of the rectangle... very useful.<P>For the second call, we're only printing a single line without wrapping, and we want it to be centered horizontally as wellas vertically (which <CODE>DrawText()</CODE> will do only when drawing a single line).<H4>Client Redraw</H4>Just a note about the example program... when the <CODE>WNDCLASS</CODE> is registered I have set the <CODE>CS_VREDRAW</CODE> and <CODE>CS_HREDRAW</CODE> class styles. This causes the entire clientarea to be redrawn if the window is resized, whereas the default is to only redraw the parts that havechanged. That looks really bad since the centered text moves around when you resize and it doesn't updatelike you'd expect.<H2>Choosing Fonts</H2>In general, any program that deals with fonts will want to let the user choose their own font, as wellas the colour and style attribute to use when displaying it.<P>Like the common dialogs for getting open and save file names, there is a common dialog for choosing a font.This is, oddly enough, called <CODE>ChooseFont()</CODE> and it works with the <CODE>CHOOSEFONT</CODE> structurefor you to set the defaults it should start with as well as returning the final result of the users selection.<PRE CLASS="SNIP">HFONT g_hfFont = GetStockObject(DEFAULT_GUI_FONT);COLORREF g_rgbText = RGB(0, 0, 0);</PRE><PRE CLASS="SNIP">void DoSelectFont(HWND hwnd){ CHOOSEFONT cf = {sizeof(CHOOSEFONT)}; LOGFONT lf; GetObject(g_hfFont, sizeof(LOGFONT), &lf); cf.Flags = CF_EFFECTS | CF_INITTOLOGFONTSTRUCT | CF_SCREENFONTS; cf.hwndOwner = hwnd; cf.lpLogFont = &lf; cf.rgbColors = g_rgbText; if(ChooseFont(&cf)) { HFONT hf = CreateFontIndirect(&lf); if(hf) { g_hfFont = hf; } else { MessageBox(hwnd, "Font creation failed!", "Error", MB_OK | MB_ICONEXCLAMATION); } g_rgbText = cf.rgbColors; }}</PRE><P>The <CODE>hwnd</CODE> in this call is simply the window you want to use as the parent for the font dialog.<P>The easiest way to use this dialog is in conjunction with an existing <CODE>LOGFONT</CODE> structure, whichis most likely from whichever <CODE>HFONT</CODE> you are currently using. We set the <CODE>lpLogFont</CODE>member of the structure to point to the <CODE>LOGFONT</CODE> that we just filled with our current informationand also added the <CODE>CF_INITTOLOGFONTSTRUCT</CODE> flag so that <CODE>ChooseFont()</CODE> knows touse this member. The flag <CODE>CF_EFFECTS</CODE> tells <CODE>ChooseFont()</CODE> to allow the userto select a colour, as well as Underline and Strikeout attributes.<P>Oddly enough, the Bold and Italics styles don't count as effects, they are considered part of the font itselfand in fact some fonts only come in Bold or Italics. If you want to check or prevent the user from selectinga bold or italic font you can check the <CODE>lfWeight</CODE> and <CODE>lfItalic</CODE> members of the <CODE>LOGFONT</CODE> respectively, after the user has made their selection. You can then prompt the userto make another selection or something change the members before calling <CODE>CreateFontIndirect()</CODE>.<P>The colour of a font is not associated with an <CODE>HFONT</CODE>, and therefor must be stored seperately,the <CODE>rgbColors</CODE> member of the <CODE>CHOOSEFONT</CODE> struct is used both to pass in the initialcolour and retreive the new colour afterward.<P><CODE>CF_SCREENFONTS</CODE> indicates that we want fonts designed to work on the screen, as opposed to fonts thatare designed for printers. Some support both, some only one or the other. Depending on what you're goingto be using the font for, this and many other flags can be found in MSDN to limit exactly which fonts youwant the user to be able to select.<H2>Choosing Colours</H2>In order to allow the user to change just the colour of the font, or to let them pick a new colourfor anything at all, there is the <CODE>ChooseColor()</CODE> common dialog. This is the codeused to allow the user to select the background colour in the example program.<PRE CLASS="SNIP">COLORREF g_rgbBackground = RGB(255, 255, 255);COLORREF g_rgbCustom[16] = {0};</PRE><PRE CLASS="SNIP">void DoSelectColour(HWND hwnd){ CHOOSECOLOR cc = {sizeof(CHOOSECOLOR)}; cc.Flags = CC_RGBINIT | CC_FULLOPEN | CC_ANYCOLOR; cc.hwndOwner = hwnd; cc.rgbResult = g_rgbBackground; cc.lpCustColors = g_rgbCustom; if(ChooseColor(&cc)) { g_rgbBackground = cc.rgbResult; }}</PRE><P>This is fairly straightforward, again we're using the <CODE>hwnd</CODE> parameter as the parent to the dialog.The <CODE>CC_RGBINIT</CODE> parameter says to start off with the colour we pass in through the <CODE>rgbResult</CODE>member, which is also where we get the colour the user selected when the dialog closes.<P>The <CODE>g_rgbCustom</CODE> array of 16 <CODE>COLORREF</CODE>s is required to store any values the user decidesto put into the custom colour table on the dialog. You could potentially store these values somewhere like theregistry, otherwise they will simply be lost when your program is closed. This parameter is not optional.<H2>Control Fonts</H2>Something else you might want to do at some point is change the font on the controls on yourdialog or window. This is usually the case when using <CODE>CreateWindow()</CODE> to createcontrols as we've done in previous examples. Controls like windows use System by default,so we used <CODE>WM_SETFONT</CODE> to set a new font handle (from <CODE>GetStockObject()</CODE>)for the control to use. You can use this method with fonts you create from <CODE>CreateFont()</CODE>as well. Simply pass the font handle as <CODE>wParam</CODE> and set <CODE>lParam</CODE> to <CODE>TRUE</CODE> to make the control redraw.<P>I've done this in previous examples, but it makes sense to mention it here because it's relevant and very short:<PRE CLASS="SNIP"> SendDlgItemMessage(hwnd, IDC_OF_YOUR_CONTROL, WM_SETFONT, (WPARAM)hfFont, TRUE);</PRE><P>Where <CODE>hfFont</CODE> is of course the <CODE>HFONT</CODE> you want to use, and <CODE>IDC_OF_YOUR_CONTROL</CODE> is the ID of whichever control you want to change the font of.<HR><FONT SIZE="-1">Copyright © 1998-2003, Brook Miles (<A HREF="mailto:forger(nospam)winprog.org">theForger</A>). 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