HDevelop User's Manual

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90 CHAPTER 4. CODE GENERATION 4.4 General Aspects of Code Generation In the following, general differences in the behavior of a HDevelop program and its exported versions are described. 4.4.1 Assignment In HDevelop each time a new value is assigned to a variable its old contents are removed automatically, independent of the type of the variable. In the exported code, this is also the case for iconic objects (C++: ÀÓØ, Visual Basic: ÀÍÒØÝÔÇØ) and for the class ÀÌÙÔÐ (C++) and the type ÎÖÒØ (Visual Basic), as they all have a destructor which removes the stored data. As the language C does not provide destructors, the generated C code calls the operators ÐÖ Ó and ×ØÖÓÝ ØÙÔÐ to remove the content of iconic output parameters (ÀÓØ) and control output parameters (ÀØÙÔÐ) before each operator call. However, problems arise if a tuple (variant) contains a handle, for example for a file, a window, or for OCR. In this case, the memory of the handle is automatically removed but not the data which it points at. In the exported programs, this data has therefore to be removed explicitely by calling the corresponding operators ÐÓ× like ÐÓ× ÓÖ or ÐÓ× ÓÚ. Please insert the ÐÓ× operators for all handles in use ¯ before a new value is assigned to a handle and ¯ at the end of the program. In Visual Basic, the ideal way would be to use the specific COM classes for this kind of data in combination with the member function. This exchange has to be done “by hand” because the export is not able to generate appropriate code. 4.4.2 ÓÖ - Loops HDevelop and the programming languages have different semantics for loops, which can cause confusion. Because the problems are so rare and the generated code would become very difficult to understand otherwise, the code generation ignores the different semantics. These differences are: 1. In the programming languages, you can modify the loop variable (e.g., by setting it to the end value of the condition) to terminate the loop. This can’t be done in HDevelop, because here the current value is stored “inside” the ÓÖ-operator and is automatically updated when it is executed again. 2. In the programming languages, you can modify the step range if you use a variable for the increment. This is also not possible with HDevelop because the increment is stored “inside” the ÓÖ-operator when the loop is entered. 3. The last difference concerns the value of the loop variable after exiting the loop. In the programming languages, it has the value with which the condition becomes false for the first time. In HDevelop it contains the end value, which was calculated when the loop was entered. HDevelop / 2000-11-16
4.4. GENERAL ASPECTS OF CODE GENERATION 91 Looking at the mentioned points we recommend to do the programming according to the following rules: 1. Don’t modify the loop variable or the step value inside the loop. If you need this behavior use the ÛÐ-loop. 2. Don’t use the loop variable after the loop. 4.4.3 System Parameters You should know that HDevelop performs some changes of system parameters of HALCON by calling the operator ×Ø ×Ý×ØÑ (see reference manual). This might cause the exported program not to produce identical output. If such a problem arises, you may query the system parameters by means of Ø ×Ý×ØÑ in HDevelop after or while running the original HDevelop version of the program. Depending to the problem, you can now modify relevant parameters by explicitly calling the operator ×Ø ×Ý×ØÑ in the exported program. 4.4.4 Graphics Windows The graphics windows of HDevelop and the basic windows of the HALCON libraries (C++: class ÀÏÒÓÛ, Visual Basic: class ÀÏÒÓÛØÖÐ, C: addressed via handles) have different functionality. ¯ Multiple windows If you use the operator Ú ÓÔÒ ÛÒÓÛ to open multiple graphics windows in HDevelop, these calls will be converted into corresponding calls of ÓÔÒ ÛÒÓÛ only for C++ and C programs. In the export of Visual Basic programs, all window operations are suppressed, because the exported code is intended to work together with the Visual Basic template. If you want to use more than one window in Visual Basic, you have to modify the code and project manually. Note, that the export of programs containing multiple windows to C++ or C might be incorrect if the ØÚØ-button was used during program execution. ¯ Window size In exported Visual Basic programs, the size of the window in the panel is predefined (½¾ ¢ ½¾) thus it will normally not fit to your image size. Therefore, you must adapt the size interactively or by using the properties of the window. ¯ Displaying results Normally, the result of every operator is displayed in the graphics window of HDevelop. This is not the case when using an exported program. It behaves like the HDevelop program running with the options: “update window = off”. We recommend to insert the operator Ú ×ÔÐÝ in the HDevelop program at each point where you want to display data. This will not change the behavior of the HDevelop program but result in the appropriate call (×Ô Ñ, ×Ô ÖÓÒ, etc.) in the exported code. When generating code for C++, close the default graphics window (using Ú ÐÓ× ÛÒÓÛ) and open a new one (using Ú ÓÔÒ ÛÒÓÛ) before the first call of Ú ×ÔÐÝ in order to assure a correct export. HALCON 6.0
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HALCON Version 6.0 MVTec Software G
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About This Manual This manual is a
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Contents 1 Introducing HDevelop 1 1
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Contents iii comment . . . . . . .
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Chapter 1 Introducing HDevelop In f
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1.2. EXAMPLE SESSION 3 Figure 1.1:
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1.2. EXAMPLE SESSION 5 Figure 1.2:
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1.3. ADDITIONAL SOURCES OF INFORMAT
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Chapter 2 Graphical User Interface
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2.3. MAIN WINDOW 11 Figure 2.1: The
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2.3. MAIN WINDOW 13 A security chec
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2.3. MAIN WINDOW 15 a directory whe
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2.3. MAIN WINDOW 17 Figure 2.7: The
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2.3. MAIN WINDOW 19 and not HDevelo
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2.3. MAIN WINDOW 21 Figure 2.10: Ma
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2.3. MAIN WINDOW 23 2.3.2.4 The Men
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2.3. MAIN WINDOW 25 Figure 2.13: On
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2.3. MAIN WINDOW 27 in a graphics w
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2.3. MAIN WINDOW 29 Figure 2.16: On
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2.3. MAIN WINDOW 31 Figure 2.17: Co
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2.3. MAIN WINDOW 33 Figure 2.18: Se
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2.3. MAIN WINDOW 35 Figure 2.20: Se
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2.3. MAIN WINDOW 37 Figure 2.23: Ex
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Page 51 and 52: 2.3. MAIN WINDOW 43 ËÙ×ØÓÒ×
Page 53 and 54: 2.3. MAIN WINDOW 45 ÏÒÓÛ º ×
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Page 57 and 58: 2.5. OPERATOR WINDOW 49 The program
Page 59 and 60: 2.5. OPERATOR WINDOW 51 Please refe
Page 61 and 62: 2.6. VARIABLE WINDOW 53 operator ha
Page 63 and 64: 2.6. VARIABLE WINDOW 55 aspect rati
Page 65 and 66: 2.7. GRAPHICS WINDOW 57 Figure 2.38
Page 67 and 68: Chapter 3 Language The following ch
Page 69 and 70: 3.2. CONTROL TYPES AND CONSTANTS 61
Page 71 and 72: 3.4. OPERATIONS ON ICONIC OBJECTS 6
Page 73 and 74: 3.5. EXPRESSIONS FOR INPUT CONTROL
Page 85 and 86: 3.6. RESERVED WORDS 77 ÓÖ, ÜÓÖ
Page 87 and 88: 3.8. LIMITATIONS 79 In the followin
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Page 91 and 92: 4.1. CODE GENERATION FOR C++ 83 Ì
Page 93 and 94: 4.1. CODE GENERATION FOR C++ 85 tha
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Page 103 and 104: 5.2. CAPILLARY VESSEL 95 ÚÐÓ×Û
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Page 107 and 108: 5.3. PARTICLES 99 each. Now it is e
Page 109 and 110: 5.4. ANNUAL RINGS 101 ÚÐÖÛÒÓ
Page 111 and 112: 5.5. BONDING 103 Figure 5.9: Exampl
Page 113 and 114: 5.7. DEVICES 105 Figure 5.11: Calib
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Page 117 and 118: 5.8. CELL WALLS 109 Figure 5.15: Mi
Page 119 and 120: 5.10. EXCEPTION HANDLING 111 Figure
Page 121 and 122: 5.11. ROAD SCENE 113 any case. All
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Page 131 and 132: 4 APPENDIX A. CONTROL Attention For
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Page 135 and 136: 8 APPENDIX A. CONTROL ÚÙÔØÛÒ
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Page 139 and 140: 12 APPENDIX B. DEVELOP Attention If
Page 141 and 142: 14 APPENDIX B. DEVELOP Ú ÓÔÒ Û
Page 143 and 144: 16 APPENDIX B. DEVELOP Ú Ò×ÔØ
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22 APPENDIX B. DEVELOP ’black’
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24 APPENDIX B. DEVELOP Parameter º
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26 APPENDIX B. DEVELOP Parameter º
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28 APPENDIX B. DEVELOP If ÊÓÛ½
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30 APPENDIX B. DEVELOP Ú ×Ø ÛÒ
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32 APPENDIX B. DEVELOP Possible Suc
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34 APPENDIX B. DEVELOP See Also Ú
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36 APPENDIX B. DEVELOP HDevelop / 2
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38 APPENDIX C. GLOSSARY Operator wi
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40 Index Ú ×Ø ÔÖØ, 27, 39 Ú
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42 Index Operator Data base, 37 Nam
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44 Index HDevelop / 2000-11-16
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