Common AlphaBitmap manipulations in Scol » History » Version 1
iri, 09/26/2012 01:10 AM
| 1 | 1 | iri | h1. Common AlphaBitmap manipulations in Scol |
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| 3 | An *AlphaBitmap* Scol object is a bitmap with an alpha channel. This alpha can be nil. |
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| 4 | It can be created from a bitmap object or it can be loaded from a PNG resource file. |
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| 5 | All functions of this API are described "here":http://www.scolring.org/files/doc_html/alpha_bitmap.html. |
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| 6 | |||
| 7 | h2. Create an AlphaBitmap |
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| 8 | |||
| 9 | h3. The ObjBitmap8 object |
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| 10 | |||
| 11 | This is 8-bits bitmap object insteaf of the 24-bits for the ObjBitmap. Lonely, it is rarely used but it can be an alpha channel. |
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| 12 | This API is near than the ObjBitmap API, see [[Common bitmap manipulations in Scol]]. |
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| 13 | |||
| 14 | We can create it from a resource file (8-bits BMP file, *_LDbitmap8*) or from ex-nihilo (*_CRbitmap8*). Like ObjBitmap, don't forget to destroy them when you no longer needed (*_DSbitmap8*). |
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| 16 | h3. AlphaBitmap |
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| 17 | |||
| 18 | The AlphaBitmap type is an opaque Scol type. |
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| 19 | Use the Scol function *_CRalphaBitmap* or *_LDalphaBitmap* to create a such object. |
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| 20 | |||
| 21 | @AlphaBitmap _CRalphaBitmap <channel> <bitmap_object> <bitmap8_object> <background_color> <transparency_color>@ |
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| 22 | The <bitmap_object> is in 24-bits (RVB), <bitmap8_object> is in 8-bits and it is the alpha channel. |
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| 23 | See "_CRalphaBitmap":http://www.scolring.org/files/doc_html/_cralphabitmap.html |
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| 24 | |||
| 25 | @AlphaBitmap _LDalphaBitmap <channel> <reference_reading_png_file> |
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| 26 | |||
| 27 | h2. Destruction |
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| 28 | |||
| 29 | When a such object is no longer needed, you should quickly destroy it with *_DSalphaBitmap*. |
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| 30 | |||
| 31 | h2. How to load a graphic resource file in Scol ? |
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| 32 | |||
| 33 | Two near ways enough near if you want to have an ObjBitmap or an AlphaBitmap. |
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| 34 | This function is helpful and you should get in your common library. |
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| 35 | |||
| 36 | <pre> |
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| 37 | /* |
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| 38 | Load a graphic resource file |
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| 39 | pfile : P : the reading-reference file |
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| 40 | channel : channel to loading |
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| 41 | return the object to create |
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| 42 | fun [P Chn] ObjBitmap |
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| 43 | fun [P Chn] AlphaBitmap |
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| 44 | */ |
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| 45 | |||
| 46 | fun loadRscFile2ObjBitmap (pFile, channel)= |
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| 47 | if pFile == nil then |
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| 48 | nil |
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| 49 | else |
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| 50 | let _LDbitmap channel pFile -> bmp in |
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| 51 | if bmp == nil then |
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| 52 | let _LDjpeg channel pFile -> jpeg in |
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| 53 | if jpeg == nil then |
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| 54 | let _LDtga channel pFile -> tga in |
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| 55 | if tga == nil then |
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| 56 | let _GETalphaBitmaps _LDalphaBitmap channel pFile -> [png _] in |
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| 57 | png |
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| 58 | else |
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| 59 | tga |
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| 60 | else |
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| 61 | jpeg |
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| 62 | else |
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| 63 | bmp;; |
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| 64 | |||
| 65 | fun loadRscFile2AlphaBitmap (pFile, channel)= |
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| 66 | if pFile == nil then |
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| 67 | nil |
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| 68 | else |
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| 69 | let _LDbitmap channel pFile -> bmp in |
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| 70 | if bmp == nil then |
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| 71 | let _LDjpeg channel pFile -> jpeg in |
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| 72 | if jpeg == nil then |
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| 73 | let _LDtga channel pFile -> tga in |
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| 74 | if tga == nil then |
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| 75 | _LDalphaBitmap channel pFile |
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| 76 | else |
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| 77 | _CRalphaBitmap channel tga nil nil nil |
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| 78 | else |
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| 79 | _CRalphaBitmap channel jpeg nil nil nil |
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| 80 | else |
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| 81 | _CRalphaBitmap channel bmp nil nil nil;; |
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| 82 | </pre> |
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| 85 |