Differenze tra le versioni di "Stampare un file con le funzioni del API di cups"
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Riga 2: | Riga 2: | ||
− | Mostriamo di seguito un semplice e breve codice per stampare un solo file: | + | Mostriamo di seguito due esempi pratici; un semplice e breve codice per stampare un solo file: |
− | + | Public Struct Cups_option_s <FONT color=gray>' ''Opzioni di stampa''</font> | |
name As Pointer <FONT color=gray>' ''Nome dell'opzione''</font> | name As Pointer <FONT color=gray>' ''Nome dell'opzione''</font> | ||
value As Pointer <FONT color=gray>' ''Valore dell'opzione''</font> | value As Pointer <FONT color=gray>' ''Valore dell'opzione''</font> | ||
− | + | End Struct | |
Library "libcups:2" | Library "libcups:2" | ||
<FONT color=gray>' ''int cupsGetDests(cups_dest_t **dests)''</font> | <FONT color=gray>' ''int cupsGetDests(cups_dest_t **dests)''</font> | ||
− | + | Private Extern cupsGetDests(dests As Pointer) As Integer | |
<FONT color=gray>' ''int cupsPrintFile(const char *printer, const char *filename, const char *title, int num_options, cups_option_t *options)''</font> | <FONT color=gray>' ''int cupsPrintFile(const char *printer, const char *filename, const char *title, int num_options, cups_option_t *options)''</font> | ||
− | + | Private Extern cupsPrintFile(stampante As String, nomefile As String, titolo As String, num_opzioni As Integer, opzioni As Cups_option_s) As Integer | |
Riga 57: | Riga 57: | ||
If err = 0 then Error.Raise("Stampa del file fallita !") | If err = 0 then Error.Raise("Stampa del file fallita !") | ||
+ | '''End''' | ||
+ | |||
+ | |||
+ | |||
+ | ed un altro un po' più complesso che utilizza altre funzioni esterne di ''CUPS'' rispetto al precedente esempio: | ||
+ | Public Struct Cups_option_s <FONT color=gray>' ''Opzioni di stampa''</font> | ||
+ | name As Pointer <FONT color=gray>' ''Nome dell'opzione''</font> | ||
+ | value As Pointer <FONT color=gray>' ''Valore dell'opzione''</font> | ||
+ | End Struct | ||
+ | |||
+ | Public Struct cups_dest_s | ||
+ | name As Pointer | ||
+ | instance As Pointer | ||
+ | is_default As Integer | ||
+ | num_options As Integer | ||
+ | options As Cups_option_s | ||
+ | End Struct | ||
+ | |||
+ | |||
+ | Library "libcups:2" | ||
+ | |||
+ | Private Const CUPS_HTTP_DEFAULT As Integer = 0 | ||
+ | Private Const HTTP_CONTINUE As Integer = 100 | ||
+ | Private Const CUPS_FORMAT_AUTO As String = "application/octet-stream" | ||
+ | |||
+ | |||
+ | <FONT color=gray>' ''cups_file_t *cupsFileOpen(const char *filename, const char *mode)'' | ||
+ | ' ''Open a CUPS file.''</font> | ||
+ | Private Extern cupsFileOpen(filename As String, mode As String) As Pointer | ||
+ | |||
+ | <FONT color=gray>' ''int cupsCreateJob(http_t *http, const char *name, const char *title, int num_options, cups_option_t *options)'' | ||
+ | ' ''Create an empty job for streaming.''</font> | ||
+ | Private Extern cupsCreateJob(http As Pointer, name As String, title As String, num_options As Integer, options As Cups_option_s) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''http_status_t cupsStartDocument(http_t *http, const char *name, int job_id, const char *docname, const char *format, int last_document)'' | ||
+ | ' ''Add a document to a job created with cupsCreateJob().''</font> | ||
+ | Private Extern cupsStartDocument(http As Pointer, name As String, jobI As Integer, docname As String, format$ As String, last_document As Integer) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''ssize_t cupsFileRead(cups_file_t *fp, char *buf, size_t bytes)'' | ||
+ | ' ''Read from a file.''</font> | ||
+ | Private Extern cupsFileRead(fp As Pointer, buf As Byte[], size_t As Integer) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''http_status_t cupsWriteRequestData(http_t *http, const char *buffer, size_t length)'' | ||
+ | ' ''Write additional data after an IPP request.''</font> | ||
+ | Private Extern cupsWriteRequestData(http As Pointer, buf As Byte[], length As Integer) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''ipp_status_t cupsFinishDocument(http_t *http, const char *name)'' | ||
+ | ' ''Finish sending a document.''</font> | ||
+ | Private Extern cupsFinishDocument(http As Pointer, name As String) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''cups_dest_t *cupsGetNamedDest(http_t *http, const char *name, const char *instance)'' | ||
+ | ' ''Get options for the named destination.''</font> | ||
+ | Private Extern cupsGetNamedDest(http As Pointer, name As String, instance As String) As Cups_dest_s | ||
+ | |||
+ | |||
+ | '''Public''' Sub Main() | ||
+ | |||
+ | Dim cups_file As Pointer | ||
+ | Dim fl, stampante As String | ||
+ | Dim id, http_stato, byte As Integer | ||
+ | Dim buffer As Byte[] <FONT color=gray>' ''Buffer di lettura/scrittura''</font> | ||
+ | Dim dest As New Cups_dest_s | ||
+ | |||
+ | |||
+ | fl = "''/percorso/del/file/da/stampare''" | ||
+ | stampante = "''nome_della_stampante''" | ||
+ | |||
+ | cups_file = cupsFileOpen(fl, "r") | ||
+ | If IsNull(cups_file) Then Error.Raise("Impossibile aprire il file !") | ||
+ | |||
+ | id = cupsCreateJob(CUPS_HTTP_DEFAULT, stampante, "testo qualsiasi", 0, Null) | ||
+ | If id <= 0 Then Error.Raise("Impossibile stampare con 'Canon-BJ-200' !") | ||
+ | Print "Processo di stampa num. "; id | ||
+ | |||
+ | http_stato = cupsStartDocument(CUPS_HTTP_DEFAULT, stampante, id, "nome documento", CUPS_FORMAT_AUTO, 1) | ||
+ | If http_stato <> HTTP_CONTINUE Then Error.Raise("Impossibile avviare la stampa del documento !") | ||
+ | |||
+ | buffer = New Byte[Stat(fl).Size] | ||
+ | |||
+ | byte = cupsFileRead(cups_file, buffer, buffer.Count) | ||
+ | While byte > 0 | ||
+ | |||
+ | If cupsWriteRequestData(CUPS_HTTP_DEFAULT, buffer, byte) <> HTTP_CONTINUE Then Error.Raise("Impossibile scrivere byte !") | ||
+ | |||
+ | Wait 0.5 | ||
+ | |||
+ | byte = cupsFileRead(cups_file, buffer, buffer.Count) | ||
+ | |||
+ | Wend | ||
+ | |||
+ | |||
+ | cupsFinishDocument(CUPS_HTTP_DEFAULT, stampante) | ||
+ | |||
+ | dest = cupsGetNamedDest(CUPS_HTTP_DEFAULT, Null, Null) | ||
+ | Print "Stampa del documento su: "; String@(dest.name) | ||
+ | |||
'''End''' | '''End''' | ||
Versione delle 13:16, 11 nov 2014
Per stampare un file con le funzioni esterne del API di CUPS (Common Unix Printing System), e dunque senza l'uso della Classe Printer, bisognerà richiamare l'attuale libreria esterna: libcups.so.2 .
Mostriamo di seguito due esempi pratici; un semplice e breve codice per stampare un solo file:
Public Struct Cups_option_s ' Opzioni di stampa name As Pointer ' Nome dell'opzione value As Pointer ' Valore dell'opzione End Struct Library "libcups:2" ' int cupsGetDests(cups_dest_t **dests) Private Extern cupsGetDests(dests As Pointer) As Integer ' int cupsPrintFile(const char *printer, const char *filename, const char *title, int num_options, cups_option_t *options) Private Extern cupsPrintFile(stampante As String, nomefile As String, titolo As String, num_opzioni As Integer, opzioni As Cups_option_s) As Integer Public Sub Main() Dim stamp_Def, predef As String Dim num_dests, err As Integer Dim p, pstmp As Pointer Dim st As Stream Dim b, j As Byte num_dests = cupsGetDests(VarPtr(p)) Print "Sono state riscontrate installate nel sistema num. "; num_dests; " stampanti:\n" ' Dereferenziando la variabile di tipo "Puntatore" si ottengono i nomi delle stampanti installate. ' In particolare ciascun nome è uguale a quello del file .ppd afferente alla stampante installata, ' presente nella cartella "/etc/cups/ppd" e privo della sua estensione. ' Il nome della stampante andrà passato, come primo argomento, alla funzione "cupsPrintFile()". st = Memory p For Read For b = 0 To num_dests - 1 Seek #st, b * 32 Read #st, pstmp Seek #st, Seek(st) + 8 Read #st, j If j = 1 Then stamp_Def = String@(pstmp) predef = " - Default\n" Endif ' Mostriamo in console il nome delle stampanti trovate installate nel sistema: Print b + 1, String@(pstmp) & predef Next ' In questo esempio passiamo alla funzione "cupsPrintFile()" il nome della stampante 'predefinita' trovata: Print "Stampa sulla stampante: "; stamp_Def st.Close() err = cupsPrintFile(stamp_Def, "/percorso/del/file/da/stampare/", "Breve titolo qualsiasi", 0, Null) If err = 0 then Error.Raise("Stampa del file fallita !") End
ed un altro un po' più complesso che utilizza altre funzioni esterne di CUPS rispetto al precedente esempio:
Public Struct Cups_option_s ' Opzioni di stampa name As Pointer ' Nome dell'opzione value As Pointer ' Valore dell'opzione End Struct Public Struct cups_dest_s name As Pointer instance As Pointer is_default As Integer num_options As Integer options As Cups_option_s End Struct Library "libcups:2" Private Const CUPS_HTTP_DEFAULT As Integer = 0 Private Const HTTP_CONTINUE As Integer = 100 Private Const CUPS_FORMAT_AUTO As String = "application/octet-stream" ' cups_file_t *cupsFileOpen(const char *filename, const char *mode) ' Open a CUPS file. Private Extern cupsFileOpen(filename As String, mode As String) As Pointer ' int cupsCreateJob(http_t *http, const char *name, const char *title, int num_options, cups_option_t *options) ' Create an empty job for streaming. Private Extern cupsCreateJob(http As Pointer, name As String, title As String, num_options As Integer, options As Cups_option_s) As Integer ' http_status_t cupsStartDocument(http_t *http, const char *name, int job_id, const char *docname, const char *format, int last_document) ' Add a document to a job created with cupsCreateJob(). Private Extern cupsStartDocument(http As Pointer, name As String, jobI As Integer, docname As String, format$ As String, last_document As Integer) As Integer ' ssize_t cupsFileRead(cups_file_t *fp, char *buf, size_t bytes) ' Read from a file. Private Extern cupsFileRead(fp As Pointer, buf As Byte[], size_t As Integer) As Integer ' http_status_t cupsWriteRequestData(http_t *http, const char *buffer, size_t length) ' Write additional data after an IPP request. Private Extern cupsWriteRequestData(http As Pointer, buf As Byte[], length As Integer) As Integer ' ipp_status_t cupsFinishDocument(http_t *http, const char *name) ' Finish sending a document. Private Extern cupsFinishDocument(http As Pointer, name As String) As Integer ' cups_dest_t *cupsGetNamedDest(http_t *http, const char *name, const char *instance) ' Get options for the named destination. Private Extern cupsGetNamedDest(http As Pointer, name As String, instance As String) As Cups_dest_s Public Sub Main() Dim cups_file As Pointer Dim fl, stampante As String Dim id, http_stato, byte As Integer Dim buffer As Byte[] ' Buffer di lettura/scrittura Dim dest As New Cups_dest_s fl = "/percorso/del/file/da/stampare" stampante = "nome_della_stampante" cups_file = cupsFileOpen(fl, "r") If IsNull(cups_file) Then Error.Raise("Impossibile aprire il file !") id = cupsCreateJob(CUPS_HTTP_DEFAULT, stampante, "testo qualsiasi", 0, Null) If id <= 0 Then Error.Raise("Impossibile stampare con 'Canon-BJ-200' !") Print "Processo di stampa num. "; id http_stato = cupsStartDocument(CUPS_HTTP_DEFAULT, stampante, id, "nome documento", CUPS_FORMAT_AUTO, 1) If http_stato <> HTTP_CONTINUE Then Error.Raise("Impossibile avviare la stampa del documento !") buffer = New Byte[Stat(fl).Size] byte = cupsFileRead(cups_file, buffer, buffer.Count) While byte > 0 If cupsWriteRequestData(CUPS_HTTP_DEFAULT, buffer, byte) <> HTTP_CONTINUE Then Error.Raise("Impossibile scrivere byte !") Wait 0.5 byte = cupsFileRead(cups_file, buffer, buffer.Count) Wend cupsFinishDocument(CUPS_HTTP_DEFAULT, stampante) dest = cupsGetNamedDest(CUPS_HTTP_DEFAULT, Null, Null) Print "Stampa del documento su: "; String@(dest.name) End