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https://github.com/QB64-Phoenix-Edition/QB64pe.git
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6e01fc8dce
Added new _STRCMP and _STRICMP commands for quick string comparisons. Cleaned up QB64 to finish removing the QUI (quick user insert) code and folders. Altered UCASE and LCASE routines to be faster in some situations for us.
85 lines
3.9 KiB
Plaintext
85 lines
3.9 KiB
Plaintext
The '''_MEMIMAGE''' function returns a [[_MEM]] value referring to an image's memory using a designated image handle.
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{{PageSyntax}}
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::: image_block = '''_MEMIMAGE'''[(''image_handle'')]
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{{Parameters}}
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* The ''image block'' [[_MEM]] type variable holds the read only .OFFSET, .SIZE, .TYPE and .ELEMENTSIZE.
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* The optional ''image handle'' requires no parameter or 0 if the image desired is the current [[_DEST]]ination program screen image.
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''Usage:''
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* Use the function to place images into memory blocks for faster data access.
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* All values created by this function MUST be freed using [[_MEMFREE]] with a valid [[_MEM]] variable type.
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''Example 1:'' Darkening an image using memory with [[$CHECKING]]:OFF for greater speed.
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{{CodeStart}} '' ''
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{{Cl|SCREEN}} {{Cl|_NEWIMAGE}}(1024, 768, 32)
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i& = {{Cl|_LOADIMAGE}}("turtle.jpg") '<<<<<<<<<<<<< use any 24 bit image file
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{{Cl|FOR...NEXT|FOR}} n! = 1 {{Cl|TO}} 0.01 {{Cl|STEP}} -0.01
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i2& = {{Cl|_COPYIMAGE}}(i&)
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DarkenImage i2&, n!
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{{Cl|_PUTIMAGE}} (0, 0), i2&
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{{Cl|_FREEIMAGE}} i2&
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{{Cl|_DISPLAY}}
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{{Cl|NEXT}}
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{{Cl|SUB}} DarkenImage (Image {{Cl|AS}} {{Cl|LONG}}, Value_From_0_To_1 {{Cl|AS}} {{Cl|SINGLE}})
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{{Cl|IF...THEN|IF}} Value_From_0_To_1 <= 0 {{Cl|OR (boolean)|OR}} Value_From_0_To_1 >= 1 {{Cl|OR (boolean)|OR}} {{Cl|_PIXELSIZE}}(Image) <> 4 {{Cl|THEN}} {{Cl|EXIT SUB}}
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{{Cl|DIM}} Buffer {{Cl|AS}} {{Cl|_MEM}}: Buffer = {{Cl|_MEMIMAGE}}(Image) 'Get a memory reference to our image
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{{Cl|DIM}} Frac_Value {{Cl|AS}} {{Cl|LONG}}: Frac_Value = Value_From_0_To_1 * 65536 'Used to avoid slow floating point calculations
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{{Cl|DIM}} O {{Cl|AS}} {{Cl|_OFFSET}}, O_Last {{Cl|AS}} {{Cl|_OFFSET}}
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O = Buffer.OFFSET 'We start at this offset
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O_Last = Buffer.OFFSET + {{Cl|_WIDTH (function)|_WIDTH}}(Image) * {{Cl|_HEIGHT}}(Image) * 4 'We stop when we get to this offset
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{{Cl|$CHECKING}}:OFF 'use on error free code ONLY!
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DO
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{{Cl|_MEMPUT}} Buffer, O, {{Cl|_MEMGET (function)|_MEMGET}}(Buffer, O, {{Cl|_UNSIGNED}} {{Cl|_BYTE}}) * Frac_Value \ 65536 {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_BYTE}}
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{{Cl|_MEMPUT}} Buffer, O + 1, {{Cl|_MEMGET (function)|_MEMGET}}(Buffer, O + 1, {{Cl|_UNSIGNED}} {{Cl|_BYTE}}) * Frac_Value \ 65536 {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_BYTE}}
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{{Cl|_MEMPUT}} Buffer, O + 2, {{Cl|_MEMGET (function)|_MEMGET}}(Buffer, O + 2, {{Cl|_UNSIGNED}} {{Cl|_BYTE}}) * Frac_Value \ 65536 {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_BYTE}}
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O = O + 4
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{{Cl|LOOP}} {{Cl|UNTIL}} O = O_Last
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{{Cl|$CHECKING}}:ON 'turn checking back on when done!
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{{Cl|_MEMFREE}} Buffer
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{{Cl|END SUB}} '' ''
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{{CodeEnd}}{{small|Code by Galleon}}
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: ''Explanation:'' The second value passed to DarkenImage is a value from 0.0 to 1.0 where 0.0 is full darkness and 1 is none.
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''Example 2:'' Reading information stored in an image with [[_MEMIMAGE]] to print [[ASC]] text characters to the screen.
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{{CodeStart}} '' ''
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{{Cl|SCREEN}} 13
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{{Cl|_FULLSCREEN}}
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{{Cl|PSET}} (0, 0), {{Cl|ASC}}("H")
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{{Cl|PSET}} (1, 0), {{Cl|ASC}}("E")
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{{Cl|PSET}} (2, 0), {{Cl|ASC}}("L")
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{{Cl|PSET}} (3, 0), {{Cl|ASC}}("L")
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{{Cl|PSET}} (4, 0), {{Cl|ASC}}("O")
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{{Cl|PSET}} (5, 0), 32
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{{Cl|PSET}} (6, 0), {{Cl|ASC}}("W")
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{{Cl|PSET}} (7, 0), {{Cl|ASC}}("O")
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{{Cl|PSET}} (8, 0), {{Cl|ASC}}("R")
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{{Cl|PSET}} (9, 0), {{Cl|ASC}}("L")
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{{Cl|PSET}} (10, 0), {{Cl|ASC}}("D")
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{{Cl|DIM}} m {{Cl|AS}} {{Cl|_MEM}}
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m = {{Cl|_MEMIMAGE}}
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x1$ = {{Cl|_MEMGET (function)|_MEMGET}}(m, m.OFFSET, {{Cl|STRING}} * 11) 'convert numbers to ASCII text characters
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{{Cl|LOCATE}} 10, 1: {{Cl|PRINT}} {{Cl|LEN}}(x1$) 'prints 11 as byte length
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{{Cl|PRINT}} x1$ 'prints HELLO WORLD
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{{Cl|END}} '' ''
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{{CodeEnd}}
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: ''Notes:'' The colors in the upper left corner are the text data used. An image could hold a hidden text message this way.
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''See also:''
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* [[_MEM]]
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* [[_MEMNEW]]
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* [[_MEMGET]], [[_MEMPUT]]
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* [[_MEMFREE]]
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* [[$CHECKING]]
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{{PageNavigation}} |