下图 显示了用 C 语言编写的、用于构建并运行 QBIC 查询的程序的一部分。图中的代码按平均颜色查询图象。它提示用户输入颜色或图象文件的名称。用户还可以将查询返回的图象用作后续查询的示例图象。该程序将命名颜色或图象的颜色用作平均颜色来查询图象列。
可在 SAMPLES 子目录中的 QBICDEMO.C 文件中找到完整的程序。可使用完整的程序按直方图颜色或位置颜色来查询图象, 以及按平均颜色查询图象。要运行完整的程序, 必须运行 ENABLE、POPULATE 和 QBCATDMO 样本程序(也在 SAMPLES 子目录中)。有关样本程序的更多信息,参见附录 B, 样本程序和媒体文件。
注意样本程序中的下列几点:
(1)包括 dmbqbapi 头文件。
(2)提示用户输入数据库信息。
(3)连接到数据库。
(4)创建查询对象。
(5)将特性添加至查询对象。
(6)提示用户提供输入类型(颜色名、图象文件或先前检索到的图象)。
(7)指定特性的数据源。数据源是对平均颜色的明确说明。
(8)发出查询。Image Extender 搜索整个图象列。它还指定 10 作为要返回的最大图象数。
(9)显示返回的图象集中的下一图象。有关显示图象的进一步信息,参见 显示实际大小的图象或视频帧。
(10)删除查询对象。
SAMPLES 子目录包括另一个用于演示如何构建并使用 QBIC 查询的程序。程序 QbicQry.java 显示了如何以图形方式指定 QBIC 查询的 搜索标准。例如,该程序提供了一个颜色选择器以选择平均颜色。该程序将选择转换为查询字符串。
#include <sql.h> #include <sqlcli.h> #include <sqlcli1.h> #include <dmbqbqpi.h> (1) #include <stdio.h> #include <string.h> #include <malloc.h> #include <color.h> #include <ctype.h> #define MaxQueryReturns 10 #define MaxDatabaseNameLength SQL_SH_IDENT #define MaxUserIdLength SQL_SH_IDENT #define MaxPasswordLength SQL_SH_IDENT #define MaxTableNameLength SQL_LG_IDENT #define MaxColumnNameLength SQL_LG_IDENT static char databaseName[MaxDatabaseNameLength+1]; static char userid[MaxUserIdLength+1]; static char password[MaxPasswordLength+1]; static char tableName[MaxTableNameLength+1]; static char columnName[MaxColumnNameLength+1]; static char line[4000]; static QbResult results[MaxQueryReturns]; static long currentImage = -1; static long imageCount = 0; static char* tableAndColumn; static QbQueryHandle averageHandle = 0; static QbQueryHandle histogramHandle = 0; static QbQueryHandle drawHandle = 0; static QbQueryHandle lastHandle = 0; static SQLHENV henv; static SQLHDBC hdbc; static SQLHSTMT hstmt; static SQLRETURN rc; static char* listQueries = "SELECT NAME,DESCRIPTION FROM MMDBSYS.QBICQUERIES ORDER BY NAME"; static char* menu[] = { /* 12345678901234567890123456789012345678901234567890123456789012345678901234567890 */ "", "+-----------------------------------------------------------------------------+", "| AVERAGE COLOR colorname |", "| AVERAGE FILE filename format |", "| AVERAGE LAST |", "| Press Enter to display the next image in the series |", "+-----------------------------------------------------------------------------+", "", 0 }; static char* help[] = { "", "AVERAGE Execute an average color query", " COLOR Specifies the color to query for", " FILE Specifies the file to compute the average color from", " LAST Specifies the last displayed image be used to compute the color", " NEXT Displays the next image from the current query or nothing if", " all of the image have been displayed." "", ">>pause<<", 0 }; /******************************************************************************/ /* doNext() */ /******************************************************************************/ static void doNext(void) { int ret; if (currentImage < imageCount) currentImage++; if (currentImage < imageCount) ret = DBiBrowse("/usr/local/bin/xv %s", MMDB_PLAY_HANDLE, results[currentImage].imageHandle, MMDB_PLAY_NO_WAIT); (9) } /******************************************************************************/ /* doAverage() */ /******************************************************************************/ static void doAverage(void) { QbQueryHandle qohandle = 0; QbImageSource is; char* type; char* arg1; char* arg2; type = nextWord(0); if (abbrev(type, "color", 1)) { is.type = qbiSource_AverageColor; arg1 = nextWord(0); if (arg1 == 0) { printf("AVERAGE COLOR command requires a colorname argument.\n"); return; } if (getColor(arg1, &is.averageColor) == 0) { printf("The colorname entered was not recognized.\n"); return; } } else if (abbrev(type, "file", 1)) { is.type = qbiSource_ClientFile; arg1 = nextWord(0); if (arg1 == 0) { printf("AVERAGE FILE command requires a filename argument.\n"); return; } arg2 = nextWord(0); if (arg2 == 0) { printf("AVERAGE FILE command requires a file format argument.\n"); return; } strcpy(is.clientFile.fileName, arg1); strcpy(is.clientFile.format, arg2); } else if (abbrev(type, "last", 1)) { is.type = qbiSource_ImageHandle; if (0 <= currentImage &&; currentImage < imageCount) strcpy(is.imageHandle, results[currentImage]imageHandle); else { printf("No last image for AVERAGE LAST command\n"); return; } } else { printf("AVERAGE command only supports COLOR, FILE, and LAST types.\n"); return; } _QbQuerySetFeatureData(averageHandle, "QbColorFeatureClass", &is); (7) _QbQuerySearch(averageHandle, tableAndColumn, "IMAGE", MaxQueryReturns, 0, 0, &imageCount, results); (8) lastHandle = averageHandle; currentImage = -1; } /******************************************************************************/ /* commandLoop() */ /******************************************************************************/ void commandLoop(void) { int done = 0; while (!done) { (6) displayText(menu); printf("%d", currentImage + 1); if (0 <= currentImage &&; currentImage < imageCount) printf(" %8.6f", results[currentImage].score); printf("> "); gets(line); done = processCommand(line); } } /******************************************************************************/ /* main() */ /******************************************************************************/ void main(void) { char* inst; int i; printf("\n\n"); printf("Please enter: database_name [user_id] [password] "\n"); (2) gets(line); if (copyWord(line, databaseName, sizeof(databaseName)) == 0) exit (0); copyWord(0, userid, sizeof(userid)); copyWord(0, password, sizeof(password)); printf("\n"); if (SQLAllocEnv(&henv) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); if (SQLAllocConnect(henv, &hdbc) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); if (SQLConnect(hdbc, (3) (SQLCHAR*)databaseName, SQL_NTS, (SQLCHAR*)userid, SQL_NTS, (SQLCHAR*)password, SQL_NTS) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); printf("Initializing . . .\n"); inst = getenv("DB2INSTANCE"); if (inst != 0 &&; strcmp(inst, "keeseyt") == 0) tableAndColumn = "KEESEY.TEST"; else tableAndColumn = "QBICDEMO.TEST"; _QbQueryCreate(&averageHandle); (4) _QbQueryAddFeature(averageHandle, "QbColorFeatureClass"); _QbQueryCreate(&histogramHandle); _QbQueryAddFeature(histogramHandle, "QbColorHistogramFeatureClass"); _QbQueryCreate(&drawHandle); _QbQueryAddFeature(drawHandle, "QbDrawFeatureClass"); (5) commandLoop(); _QbQueryDelete(drawHandle); _QbQueryDelete(histogramHandle); (10) _QbQueryDelete(averageHandle); if (SQLDisconnect(hdbc) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); if (SQLFreeConnect(hdbc) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); if (SQLFreeEnv(henv) != SQL_SUCCESS) sqlError(SQL_NULL_HSTMT); } |