Windows Programming Learning Notes-text and fonts

BOOL TextOut (
inch HDC HDC,
in int nxstart,
in int nystart,
inch LPCTSTR lpstring,
in int cchstring
);

Writes a string at the specified location. Uses the currently selected font, background color, font color.

Nxstart: The x-coordinate of the reference point used by the system to align the string. Logical coordinates.
Nystart

The interpretation of the reference point depends on the current text alignment mode. This mode can be obtained with gettextalign.
You can change this mode with SetTextAlign.
Ta_baseline: Reference point at baseline.
Ta_bottom: The reference point is at the bottom of the bounding rectangle.
Ta_top: The reference point is at the top of the bounding rectangle.

Ta_center: The reference point is in the middle of the bounding rectangle.
Ta_left: Reference points to the left of the bounding rectangle
Ta_right: Reference point re-bounds rectangle right
TA_NOUPDATECP: The reference point is not updated after the text output.

TA_UPDATECP: Reference points are updated after each text output. When in this mode, TextOut's Nxstart,nystart is ignored.

LONG TabbedTextOut (
inch HDC HDC,
in int X,
in int Y,
inch LPCTSTR lpstring,
in int ncount,
in int ntabpositions,
in const lpint lpntabstoppositions,
in int ntaborigin
);

Writes a string at the specified position. Expands tabs to the specified value in the Tab-stop location array. The text is written with the currently selected font, background color, and text color.
HDC: Device Environment handle
X: The x-coordinate of the starting point of the string. Logical units.
Y: the y-coordinate of the starting point of the string. Logical units.
Lpstring: Points to the string to write.
Lpstring: Length of string write.
nTabPositions: The number of values in the Tab-stop position array.
lpnTabStopPositions: points to an array that contains the tab-stop position in logical units. Tab-stops need to be arranged in ascending order. The minimum x value should be the first entry in the array.
nTabOrigin: Start position x coordinate. Tabs is expanded from here. Logical units.

return value:
Success, dimensions. The height is high-order word. The width is the low-order word.
Failed, 0.

Virtual BOOL ExtTextOut (
int x,
int y,
UINT Noptions,
Lpcrect LpRect,
LPCTSTR lpszstring,
UINT Ncount,
Lpint lpdxwidths
);

Writes a string using the selected font within a rectangular area.
X: Specifies the logical x-coordinate of the first character.
Y: Specifies the top logical y-coordinate of the first character.
Noptions:
Eto_clipped: Specifies that the text is clipped to a rectangle.
Eto_opaque: Fills the rectangle with the current background color.
LpRect: A dimension that points to a rectangular structure to define a rectangle.
Lpszstring: String.
Ncount: The number of characters to be processed in the string.
Lpdxwidths: Points to an array. Each element represents the distance from the starting point of the adjacent character cell. Is null, the default character spacing is used.

Int DrawText (
in hdc hdc,
Inout lpctstr lpchtext,
in int ncount,
Ino UT LPRECT LPRECT,
in UINT uformat
);

Draws the formatted text in the specified rectangle. Method according to the specified method format. You can specify additional formatting options with Drawtextex.
HDC: Device Environment handle
Lpchtext: A pointer to a string to be displayed. When Ncount is-1, the string needs to have a terminating character.
This function can add 4 additional characters to a string when Uformat contains dt_modifystring. The character buffer should be large enough to accommodate extra characters.
Ncount: The length of the string in characters. If Ncount is -1,lpchtext, it should end with a terminator. DrawText automatically calculates the number of characters.
LpRect: A rectangle that points to the location where a string is formatted. Logical coordinates.
Uformat: A method for formatting strings.
Dt_bottom: Adjusts the string to the bottom of the rectangle. Valid only when the Dt_singleline is set.
Dt_calcrect: Determines the width and height of the rectangle.
If there is more than one line of text, DrawText uses the rectangle that the lprect points to, extending the base of the rectangle to the bounds of the last line of text.
If the largest word is wider than the rectangle, the width of the rectangle expands accordingly.
If the text is smaller than the rectangle width, the width decreases accordingly.
If the text has only one row, DrawText modifies the right side of the rectangle so that it contains the last character in a row.
In other cases, DrawText returns the height of the formatted text, but does not draw the text.
Dt_center: Centers the text horizontally in the rectangle.
Dt_editcontrol: Copies the text display properties of a multiline control.
In particular, the average character justifies is computed in the same way and the function does not display the last line that is visible in a section.
Dt_end_ellipsis: For displayed text, if the end part of a string does not fit in the rectangle, it is truncated and the ellipsis is added.
If a word is not at the end of the string and exceeds the bounds of the rectangle, it is truncated but does not add an ellipsis.
This string was not modified unless the dt_modifystring identity was specified.

Dt_expandtabs: Extended tab character. Each tab has a default of 8 characters.
Dt_word_ellipsis, Dt_path_ellipsis, and dt_end_ellipsis cannot be shared with Dt_expandtabs.

Dt_externalleading: Contains the font outer space in the height of the row. The outer space is usually not included in the height of a line of text.
Dt_hideprefix:
Dt_internal: Calculates text metrics with system fonts.
Dt_left: The text is left-justified.
Dt_modifystring: Modifies the specified string to match the display text.
Dt_end_ellipsis or dt_path_ellipsis is valid when specified.

Dt_noclip: No cut draw.
Dt_nofullwidthcharbreak: Prevents a row from breaking in a Gemini justifies string. So that the line break rule is equivalent to a single character string.
Valid when Dt_wordbreak is not specified.

Dt_path_ellipsis: The ellipsis is used to replace the characters in the middle of the string with the displayed text. To fit the specified rectangle.
If the string contains a backslash character, Dt_path_ellipsis saves as many backslash characters as possible.

Dt_right: Right-justified
Dt_singleline: Displays text on one line.
Dt_tabstop: Sets the number of tab positions.
The high byte of the low word of Uformat specifies the number of characters per tab.
Dt_calcrect, Dt_externalleading, Dt_internal, Dt_noclip, and Dt_noprefix are not and dt_tabstop common.

Dt_top: Aligns the top of the text.
Dt_vcenter: vertically centered. Dt_singleline is set in effect.

Dt_wordbreak: Interrupts the word. Lines are automatically interrupted between words if the word expands beyond the bounding rectangle specified by the lprect parameter. When not specified, the output is in one row.

Dt_word_ellipsis: Truncate word does not fit rectangle, add ellipsis.

Successful, returns the text height. Logical units.
When Dt_vcenter or Dt_bottom is specified, the return value is the offset lprect->top to the bottom of the drawing text.
Failed, 0

The text alignment mode of the device environment includes Ta_left, Ta_top, and TA_NOUPDATECP

Text color:
SetTextColor: Text color
SetBkMode: Background mode. Qpaque: Fills the rectangle with the currently set background color. TRANSPARENT.
SetBkColor

SetTextColor (hdc, GetSysColor (Color_windowtext));
SetBkColor (hdc, GetSysColor (Color_window));

Character spacing: The default value is 0.
SetTextCharacterExtra (hdc, Iextra); Iextra is a logical unit.
Gettextcharacterextra.

Font

The typeface and font size of the text define a specific font.

Working with inventory fonts
Hfont Hfont = Getstockobject (IFont); IFont can be used to take values in some of the identifiers that are predefined by window.
SelectObject (hdc, Hfont);

When specifying a new font in the device environment, call Gettextmetrixs to calculate the character height and the average width of the characters in the font.

Windows supports GDI fonts and device fonts.
GDI fonts are stored in hard disk files. Device fonts are supported by the output device itself.

GDI fonts are divided into three categories: bitmap fonts, stroke fonts, and TrueType fonts.

Each character in the bitmap font is represented in pixels and stored in a bitmap, also known as a bitmap font.
Each bitmap font is designed for specific dimensions and aspect ratios of characters.

Lattice font typeface name:
System
Fixedsys
Terminal
Courier
MS Serif
MS Sans Serif
Small Fonts

Each bitmap font has only a few limited dimensions.

Stroke font. Stroke fonts consist of a series of points and line segments of the connection points.
Stroke fonts can be scaled in a smooth manner.

Stroke Font typeface name:
Modern
Roman
Script

For GDI bitmap fonts and GDI stroke fonts, the different glyphs can be directly synthesized.

Each character of a TrueType font is defined by the outline of the character.
Windows can resize a TrueType font by changing the coordinates of the character footprints.

Typeface name for TrueType fonts:
Courier New
Courier New Bold
Courier New Italic
Courier New Bold Italic
Times New Roman
Times New Roman Bold
Times New Roman Italic
Times New Roman Bold Italic
Arial
Arial Bold
Arial Italic
Arial Bold Italic
Symbol

When you set italic or bold, you can use properties or use the same series of different words to achieve the same purpose.

Logical font

A logical font is a GDI object.

BOOL CreateFontIndirect (
Const logfont* lpLogFont
);
Initializes a CFont object with the given attribute within the LOGFONT structure.

typedef struct TAGLOGFONT {
LONG lfheight;
LONG Lfwidth;
LONG lfescapement;
LONG lforientation;
LONG Lfweight;
BYTE Lfitalic;
BYTE Lfunderline;
BYTE lfstrikeout;
BYTE lfCharSet;
BYTE lfoutprecision;
BYTE lfclipprecision;
BYTE lfquality;
BYTE lfpitchandfamily;
TCHAR Lffacename[lf_facesize];
} LOGFONT;

Lfheight: Specifies the height of the font character cell. Logical units.
The character height value is the value of the character cell height minus the internal value.

0 Font mapping Converts this value to device units and matches the cell height at which it is available for the font.
0 font mapping uses a default height value.
<0 Font mapping Converts this value to device units, matching the height at which he gets the absolute value of the font to be obtained.

For mm_text mapping mode, use the following rules to set the height of the font for fixed-point values.
Lfheight =-muldiv (pointsize, GetDeviceCaps (HDC, Logpixelsy), 72);

Define MULDIV (A,b,c) (((a) * (b))/(c))

Lfwidth: Specifies the average width of characters in the font. Logical units.
If Lfwidth is not 0, the device aspect ratio matches the digital aspect ratio of the available font to find the closest match.
The Tmavecharwidth field corresponding to the textmetric.
How to use:
Set LogFont's lfwidth to 0, create a logical font and select it in the device environment
Then use GetTextMetrics to get the Tmavecharwidth field, proportionally adjust the size of the value,
Creates a new font with the adjusted tmavecharwidth value as the Lfwidth field value.

Lfescapement: The number of pre-defined displacements of the text.
Specify the angle to 10 degrees. Between the line distance vector and the x-axis.
The leading vectors are parallel to the baseline of the line of text.
If lfescapement specifies escapement and orientation, the lforientation should also be set to the same value.

Lforientation: Text pre-defined direction.
Specify the angle to 10 degrees. Between the's baseline line and the x-axis of each word.

To allow two fields to have the effect described above, you must satisfy:
With TrueType fonts,
Running on Windows NT,
The cm_advanced flag that was set when the SetGraphicsMode was previously called.

The unit is One-tenth degrees. Measured from counterclockwise direction.
lpescapement Specifies the size of the displacement between adjacent characters in the output string.
Lforientation the tilt direction of a single character.

Lfweight: Specifies the font weight, in the range [0, 1000]. 0 o'clock with default weights.

Lfitalic: Specifies a italic font.

Lfunderline: Specifies an underscore font.

Lfstrikeout: Specifies a strikethrough font.

lfCharSet: Specifies the character set.

Ansi_charset
Baltic_charset
Chinesebig5_charset
Default_charset
Easteurope_charset
Gb2312_charset
Greek_charset
Hangul_charset
Mac_charset
Oem_charset
Russian_charset
Shiftjis_charset
Symbol_charset
Turkish_charset

Lfoutprecision: Specifies the output precision.
The output precision defines how the output must match the height, width, character orientation, escapement,pitch, and font type of the requested font exactly.

Out_default_precis: Specifies the default font mapping behavior.
Out_raster_precis: Instructs font mapping to select a raster font when the system contains multiple fonts with the same name.
Out_string_precis: Not used by font mapping. But is returned when the raster font is enumerated.

Lfclipprecision: Specifies the cut precision.
The cut precision defines how to cut the characters that go beyond the clipping area.

Clip_default_precis: Specifies the default clipping behavior.
Clip_character_precis: Not used.
Clip_stroke_precis: Not used by font mapping. However, when a raster, container, or TrueType font is enumerated, it is returned.

Lfquality: Specifies the output quality.
The output quality defines how GDI is careful to match logical font attributes to these actual physical fonts.

Antialiased_quality:
Nonantialiased_quality: Force the use of draft quality. When hkey_local_machine\ system\ gdi\ fontsmoothing The registry subkey is used.
Cleartype_compat_quality: Use CLEARTYPE text for compatible width fonts.
Cleartype_quality: Use CLEARTYPE text for fonts.
The display driver must support ClearType text.
Default_quality: Font appearance is not important.
Draft_quality: For GDI raster fonts, enable zooming.

Lfpitchandfamily: Specifies the font spacing and group.
Two low-order bits specify the font spacing, but the following values:
Default_pitch
Fixed_pitch
Mono_font
Variable_pitch

4-7-bit Specifies the font group, but the following values:
Ff_decorative
Ff_dontcare
Ff_modern
Ff_roman
Ff_script
Ff_swiss
The font family describes the appearance of a font commonality.
They are intended with the specified font when additional typeface are not available. The following values are desirable:
Ff_decorative:
Ff_dontcare:
Ff_modern: The font has a variable stroke width.
such as Pica, Elite, and Courier New.
Ff_roman: The font has a varying stroke width and liner.
such as serif.
Ff_script: Handwriting font.
such as script and cursive.
Ff_swiss: The font has a varying stroke width without a liner.
such as Sans Serif.

Lffacename: A string that specifies the typeface name of the font.
Length (with Terminator) no more than 32 fonts, when NULL, GDI uses the first font that matches other specified properties

The situation does not support ClearType antialiasing.
The text is presented on the printer.
Displays a color that is set to 256 or less.
The text is presented in a Terminal Services client.
The font is not a TrueType font or a Microsoft OpenType font with TrueType external lines.
Fonts have embedded bitmaps

Lfheight represents the point value X number of pixels
if (flogres)
{
LOGPIXELSX: Number of pixels per logical inch along screen width logpixelsy: number of pixels per logical inch along screen height
cxdpi = (FLOAT) getdevicecaps (hdc, LOGPIXELSX);
cydpi = (FLOAT) getdevicecaps (hdc, logpixelsy);
}
Else
{
Horzres: Width of screen (pixels) vertres: Height of screen (raster line)
Horzsize: The width of the physical screen (mm) Vertsize: The height of the physical screen (mm)
The number of pixels per physical inch Unit is calculated
cxdpi = (FLOAT) (25.4 * GETDEVICECAPS (HDC, horzres)/GetDeviceCaps (hdc, horzsize));
cydpi = (FLOAT) (25.4 * GETDEVICECAPS (HDC, vertres)/GetDeviceCaps (hdc, vertsize));
}

 // 1磅约为1/72英寸 // 每磅像素数。点值。 pt.x = (int) (iDeciPtWidth  * cxDpi / 72) ; pt.y = (int) (iDeciPtHeight * cyDpi / 72) ; DPtoLP (hdc, &pt, 1) ; // tmHeight - tmInternalLeading，字体中字符高度占据的空间是多少磅。也就是字体的点值 lf.lfHeight         = - (int) (fabs (pt.y) / 10.0 + 0.5) ;

Font matching algorithm:
lfCharSet is important.
This value is important when the Lppitchandfamily field contains FIEXED_PITC.
Lpfacename is also important.
For bitmap fonts, Windows tries to match the Lfheight value. For notes and bitmap fonts, Windows uses simple scaling to get the desired font height.
When Lfquality is proof_quality, you can prevent Windows from zooming in on the bitmap font.
Lfheight and Lfweight are worth the ratio and the display aspect ratio does not match, Windows looks for the corresponding bitmap font.

typedef struct TAGTEXTMETRICW
{
LONG Tmheight; The logical unit represents a high character. Lfheight > 0, both short-sighted equal, both refers to the line spacing. Lfheight < 0,tmheight-tminternalleading is the absolute value of the lfheight and is also the point.
LONG tmascent; Logical units. The vertical length of the character above the baseline.
LONG tmdescent; Logical units. The vertical length of the character below the baseline.
LONG tminternalleading; The internal interval value. The area that corresponds to the uppercase diacritical marks. Tmheight already contains this area.
LONG tmexternalleading; External interval value
LONG Tmavecharwidth; Average width of lowercase letters
LONG Tmmaxcharwidth; The width of the widest character in the font. Logical units.
LONG Tmweight; The degree of character thickness. 0-999
LONG TmOverhang; When Windows makes italic or bold compositing of a bitmap font, the character becomes slightly wider. This field represents that extra width.
LONG Tmdigitizedaspectx; The aspect ratio that fits the font
LONG tmdigitizedaspecty; The aspect ratio that fits the font
WCHAR Tmfirstchar; The encoding of the first character in a font
WCHAR Tmlastchar; The encoding of the last character in a font
WCHAR Tmdefaultchar; When the character that you want to display does not exist in the font, Windows uses the character defined by this paragraph instead of the display.
WCHAR Tmbreakchar; Windows thinks it can be a break at that character.
BYTE Tmitalic; is the italic word. Not 0, which represents an italic font
BYTE tmunderlined; is underlined, not 0, with underscores
BYTE tmstruckout; With strikethrough, not 0, indicating strikethrough
BYTE tmpitchandfamily; The low four bits of the field represent some of the characteristics of the font. The high four-bit represents the series of fonts.
BYTE tmcharset;//Character Set
} TEXTMETRICW, *PTEXTMETRICW, near *nptextmetricw, far *LPTEXTMETRICW;

Font Enumeration

int Enumfonts (
inch HDC HDC,
inch LPCTSTR Lpfacename,
inch Fontenumproc Lpfontfunc,
inch LPARAM LPARAM
);

Lpfacename is null, enumerating all fonts. Non-null to return a specific font.
Lpfontfunc: Enumerates the callback functions.
LParam: Optional. Can be used to pass parameters to the enumeration callback function.

int EnumFontFamilies (
inch HDC HDC,
inch LPCTSTR lpszfamily,
inch Fontenumproc Lpenumfontfamproc,
inch LPARAM LPARAM
);

Lpszfamily is set to null the first time it is called.
For each font family, a lpenumfontfamproc is called once.
The application then calls EnumFontFamilies again with each typeface name in the font family, but uses a different callback function at a time.
For each font in the series, GDI invokes the second incoming callback function.

typedef struct
{
DWORD lStructSize;
HWND hWndOwner;
HDC hdc;
lpLogFont lpLogFont;
INT ipointsize;
DWORD Flags;
COLORREF rgbcolors;
LPARAM Lcustdata;
Lpcfhookproc Lpfnhook;
LPCTSTR Lptemplatename;
HINSTANCE hinstance;
LPTSTR Lpszstyle;
WORD nFontType;
INT nsizemin;
INT Nsizemax;
} Choosefont, *lpchoosefont;

Contains the information that the Choosefont function uses to initialize the Font selection dialog box.
When the dialog box is closed, the system returns the user selection information in this structure.

LSTRUCTSIZE: Structure length. BYTE units.
hWndOwner: Handle, point to the window that owns the dialog box.
HDC: Invalid
lpLogFont: points to a LOGFONT structure.
If Cf_inittologfontstruct is set in the Flags field and the other members are initialized,
The Choosefont Function Initialization dialog box uses a font that matches the LogFont member. If the user clicks the OK button, Choosefont
Sets the LOGFONT structure member based on the user's selection.
Ipointsize: Font size, 1/10-point value unit.
Flags: A bit collection that you can use to initialize the Font dialog box. When the dialog box returns, it sets these bits to indicate user input. Can be the following values:
Cf_apply: Let the dialog box show the APPLY button.
You should provide a hook processor to handle the WM_COMMAND message of the Apply button.
The hook processor can send a Wm_choosefont_getlogfont message to the dialog box to obtain a structure address that contains the font selected by the current user.
Cf_ansionly: No.
Cf_both: not considered.
Cf_effects: Lets the dialog box display the control, which refers to the strikethrough, underline, and text color options.
If this flag is set, you can use the Rgbcolors member to specify the initial text color. You can use this structure to lplogfont the lfstrikeout and Lfunderline
Member to specify the strikethrough and Underline check box initial settings.
Select the font function to return the user selection with several members mentioned above.
Cf_enablehook: Enable the hook processor specified in this fabric Lpfnhook
Cf_enabletemplate:
Indicates that hinstance and lptemplatename specify a template to use.
Cf_enabletemplatehandle:
Indicates that the hinstance specifies a block of data that contains the pre-loaded dialog box template.
If this flag is specified, the system ignores lptemplatename.
Cf_fixedpitchonly:choosefont only enumerates equal-width fonts.
Cf_forcefontexist:choosefont should specify an error condition if the user tries to select a font or style without listing in the dialog box.
Cf_inittologfontstruct:
Choosefont applies the lpLogFont pointer to the structure to initialize the dialog box control.
Cf_limitsize:choosefont The font size you choose should be between Nsizemin and Nsizemax.
Cf_nooemfonts: Same as cf_novectorfonts.
Cf_nofacesel:
When using the LOGFONT structure to initialize the dialog box control, use this flag to block the dialog box from displaying an initial selection for a font name combo box.

Cf_noscriptsel: No consideration
Cf_nosimulations: Do not display, do not allow font emulation.
Cf_nosizesel:
When this dialog control is initialized with a structure, this flag is used to prevent the dialog box from displaying the initial selection of the Font size check box.
Cf_nostylesel:
When a LOGFONT structure Initializes a dialog box control, this flag is used to prevent the dialog box from displaying the initial selection of the Font style check box.
Cf_novectorfonts:
Choosefont does not allow vector font selection.

Cf_novertfonts: Let the Font dialog box list only the horizontal font.
Cf_printerfonts: not considered.
Cf_scalableonly: not considered.
Cf_screenfonts: not considered.

Cf_scriptsonly: not considered.
Cf_ttonly: not considered.
Cf_selectscript:
When the input specifies a character set that is defined only in lfCharSet with LogFont, the font is displayed.
The user is not allowed to change the font set in the Scripts check box.
Cf_showhelp:
To have the dialog box display the Help button, hWndOwner must specify a window to accept the helpmsgstring registration message.
This message is sent when the Help button is pressed in the dialog box.
Cf_usestyle:
This Lpszstyle member is a pointer to a buffer that contains style data. The Choosefont is used to initialize the font style check box.
The user closes the dialog box, and this buffer saves the user's choice.
CF_WYSIWYG: invalid.

Rgbcolors:
When the CF_EFFECTS flag is set, rgbcolors specifies the initial text color.
When Choosefont returns successfully, this member contains the RGB value of the text color selected by the user.
Lcustdata:
By applying the defined data, the system is passed to the hook processor, defined by the Lpfnhook member.
When the system sends a WM_INITDIALOG message to the hook processor, the lparam parameter of the message is a pointer to the CHOOSEFONT structure.
The hook processor can use pointers to get lcustdata values.
Lpfnhook:
A pointer to the CFHOOKPROC hook processor that handles the message for the dialog box.
Valid only when the CF_ENABLEHOOK flag is set.
Lptemplatename:
dialog box template resource name. The template defaults to the Standard dialog box template.
Valid only when the CF_ENABLETEMPLATE flag is set.
HINSTANCE:
If the CF_ENABLETEMPLATEHANDLE flag is set, HINSTANCE is a handle to the memory object. The Memory object contains a dialog box template.
If the CF_ENABLETEMPLATE flag is set, HINSTANCE is a handle that points to a module that contains the Lptemplatename specified dialog box template.

Lpszstyle:
Cf_usestyle is set in effect.

nFontType:
When Choosefont returns, the font type used to represent the selection.
Bold_fonttype
Italic_fonttype
Printer_fonttype
Regular_fonttype
Screen_fonttype
Simulated_fonttype

Nsizemin
Nsizemax

The Lfheight field of the LOGFONT structure set by Choosefont is always in pixels. and is only suitable for video display.

Windows Programming Learning Notes-text and fonts